Changed requestOptions as function so that we can change options depending on the request

Author: dinumathai

packages/openapi-to-graphql/README.md

@@ -176,12 +176,10 @@ Resolver options:
 
 - `qs` (type: `object`, default: `{}`): Query parameters to be sent in every request to the API. Parameters defined in the OpenAPI Specification and set by these query parameters will be ignored by OpenAPI-to-GraphQL.
 
-- `requestOptions` (type: `object`, default: `{}`): Additional [options](https://github.com/request/request#requestoptions-callback), provided by the [`Request` module](https://github.com/request/request), that can be used to configure the HTTP calls that powers the generated GraphQL resolvers. A common use case for this option is to set up a web proxy with the `proxy` field. Parameters defined in the OpenAPI Specification and  set by this option will be ignored by OpenAPI-to-GraphQL. Additionally, the `headers` field has the feature of being used as a function. If used as a function, the following parameters will be exposed per-request: the operation's `method`, the operation's `path`, the API `title`, and `resolverParams` (the [GraphQL resolver's parameters](https://graphql.org/learn/execution/#root-fields-resolvers)). The function should return the desired headers.
+- `requestOptions` (type: `object` | `function`, default: `{}`): Additional [options](https://github.com/request/request#requestoptions-callback), provided by the [`Request` module](https://github.com/request/request), that can be used to configure the HTTP calls that powers the generated GraphQL resolvers. A common use case for this option is to set up a web proxy with the `proxy` field. Parameters defined in the OpenAPI Specification and  set by this option will be ignored by OpenAPI-to-GraphQL. Additionally, the `headers` field has the feature of being used as a function. If used as a function, the following parameters will be exposed per-request: the operation's `method`, the operation's `path`, the API `title`, and `resolverParams` (the [GraphQL resolver's parameters](https://graphql.org/learn/execution/#root-fields-resolvers)). The function should return the desired headers. If `requestOptions` is used as a function, the following parameters will be exposed per-request: the operation's `method`, the operation's `path`, the API `title`, and `resolverParams` (the [GraphQL resolver's parameters](https://graphql.org/learn/execution/#root-fields-resolvers)). It should return object of type [options](https://github.com/request/request#requestoptions-callback). If `requestOptions` is used as a function `url` and `method` can also be set.
 
 - `baseUrl` (type: `string`): Used to manually specify the base URL which all paths will be built on. Normally, OpenAPI-to-GraphQL will select a base URL from the [server object](https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.2.md#serverObject) defined in the OAS. However, if the server object contains multiple URLs, OpenAPI-to-GraphQL will randomly select one. The purpose of this option is to provide greater control over the base URL in these situations, especially when the OAS cannot be modified. This option may also prove to be useful in testing and development.
 
-- `urlResolver` (type: `object` | `function`, default: `{}`): URL used to send every request to the API. The following parameters will be exposed per-request: the operation's `method`, the operation's `path`, the API `title`, and `resolverParams` (the [GraphQL resolver's parameters](https://graphql.org/learn/execution/#root-fields-resolvers)). The function should return the desired url.
-
 - `customResolvers` (type: `object`, default: `{}`): OpenAPI-to-GraphQL, by default, creates resolver functions that make REST calls to resolve Query and Mutation fields in the generated GraphQL interface. This option allows users to provide custom resolver functions to be used in place of said ones created by OpenAPI-to-GraphQL. The field that the custom resolver will affect is identifed first by the [title](https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.2.md#infoObject) of the OAS, then the [path](https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.2.md#paths-object) of the operation, and lastly the [method](https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.2.md#path-item-object) of the operation. The `customResolvers` object is thus a triply nested object where the outer key is the title, followed by the path, and finally the method, which points to the [resolver function](https://graphql.org/learn/execution/#root-fields-resolvers) itself. The resolver function can use the parameters `obj`, `args`, `context`, and `info` in order to produce the proper data, as do standard [resolver functions](https://graphql.org/learn/execution/#root-fields-resolvers) in GraphQL. Use cases include the resolution of complex relationships between types, implementing performance improvements like caching, or dealing with non-standard authentication requirements. _Note: Because the arguments are provided by the GraphQL interface, they may look different from the [parameters](https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.2.md#parameterObject) defined by the OAS. For example, they will have [sanitized](https://github.com/IBM/openapi-to-graphql#characteristics) names. The [request body](https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.2.md#requestBodyObject) will also be contained in the arguments as an [input object type](https://graphql.org/graphql-js/mutations-and-input-types/)._
 
 - `customSubscriptionResolvers` (type: `object`, default: `{}`): If the `createSubscriptionsFromCallbacks` is enabled, OpenAPI-to-GraphQL will generate Subscription fields. This option allows users to provide custom resolver and subscribe functions to be used in place of said ones created by OpenAPI-to-GraphQL. The field that the custom resolver and subscribe functions will affect is identifed first by the [title](https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.2.md#infoObject) of the OAS, then the [path](https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.2.md#paths-object) of the operation, and lastly the [method](https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.2.md#path-item-object) of the operation. The resolver is provided via the `resolver` field and the publish function is provided via the `publish` field. The `customSubscriptionResolvers` object is thus a quadruply nested object where the outer key is the title, followed by the path, then the method, and lastly either `resolver` or `publish` which points to the [resolver function](https://graphql.org/learn/execution/#root-fields-resolvers) itself or publish function. See the [Subscriptions tutorial](./docs/subscriptions.md) for more information. _Note: Because the arguments are provided by the GraphQL interface, they may look different from the [parameters](https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.2.md#parameterObject) defined by the OAS. For example, they will have [sanitized](https://github.com/IBM/openapi-to-graphql#characteristics) names. The [request body](https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.2.md#requestBodyObject) will also be contained in the arguments as an [input object type](https://graphql.org/graphql-js/mutations-and-input-types/)._