Fix bad link (#6597)

The linked page was removed in 6909684d6, and the section was readded to
a new page in 1ecdd2d73.

Author: siiky

guides/deployment/releases.md

@@ -268,7 +268,7 @@ A few points about configuring a containerized application:
 
 - The more configuration you can provide at runtime (using `config/runtime.exs`), the more reusable your images will be across environments. In particular, secrets like database credentials and API keys should not be compiled into the image, but rather should be provided when creating containers based on that image. This is why the `Endpoint`'s `:secret_key_base` is configured in `config/runtime.exs` by default.
 
-- If possible, any environment variables that are needed at runtime should be read in `config/runtime.exs`, not scattered throughout your code. Having them all visible in one place will make it easier to ensure the containers get what they need, especially if the person doing the infrastructure work does not work on the Elixir code. Libraries in particular should never directly read environment variables; all their configuration should be handed to them by the top-level application, preferably [without using the application environment](https://hexdocs.pm/elixir/library-guidelines.html#avoid-application-configuration).
+- If possible, any environment variables that are needed at runtime should be read in `config/runtime.exs`, not scattered throughout your code. Having them all visible in one place will make it easier to ensure the containers get what they need, especially if the person doing the infrastructure work does not work on the Elixir code. Libraries in particular should never directly read environment variables; all their configuration should be handed to them by the top-level application, preferably [without using the application environment](https://hexdocs.pm/elixir/design-anti-patterns.html#using-application-configuration-for-libraries).
 
 ## Clustering