Implement casing of :byte type

[gmile]

The documentation mentions all types from OpenAPI spec to be recognized and cast:

open_api_spex/lib/open_api_spex/cast.ex

Lines 52 to 58 in def1794

	Recognizes all the types defined in Open API (itself a superset of JSON Schema).
	JSON Schema types:
	[https://json-schema.org/latest/json-schema-core.html#rfc.section.4.2.1](https://json-schema.org/latest/json-schema-core.html#rfc.section.4.2.1)
	Open API primitive types:
	[https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.0.md#data-types](https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.0.md#data-types)

However, it appears :byte type, e.g. a base64-encoded value, is not being handled e.g. decoded from Base64.

[zorbash]

Thanks for reporting this @gmile
Would you be interested in submitting a PR to implement this behaviour?

[gmile]

@zorbash sure, here's my attempt at addressing this one: #504

[mbuhot]

Fixed in #504 thanks @gmile 👍