fix(api): add additional header during subscription authorization

[sayasheng]

• PR title and description conform to Pull Request guidelines.

Issue #, if available:
Custom headers set in interceptor are missing during subscription authorization
Description of changes:

1. define new function addAdditionalHeader in AWSApiPlugin.java
2. set the additional header in SubscriptionAuthorizer.java

How did you test these changes?
HashMap<String, String> additionalHeaders = new HashMap<>();
additionalHeaders.put("test", "This is a test");
AWSApiPlugin apiPlugin = AWSApiPlugin.builder()..addAdditionalHeader(additionalHeaders).build();

Documentation update required?

• No
• [ x ] Yes (Please include a PR link for the documentation update)

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[mikepschneider]

@sayasheng, can you provide the reasoning for needed to add additional headers?

Also please update your PR to follow the submission guidelines

[sayasheng]

@sayasheng, can you provide the reasoning for needed to add additional headers?

@mikepschneider Our backend team set up Web Application Firewall (WAF) for query/mutation/subscription, it needs to give custom headers during query/mutation/subscription. Using interceptor to inject the custom headers works only on query/mutation. It fails to set the custom headers during subscription. That's why I made the modification.

Also please update your PR to follow the submission guidelines
Thank you for this information. I will follow the guidelines to update my PR.

[titanjer]

@mikepschneider hi, any updates?

[manueliglesias]

Hi @sayasheng , @titanjer ,

Can you take a look at #2283 ? It should, among other things, cover your use case

[gpanshu]

Closing this PR as the changes were done as part of #2283 . Feel free to open a new PR if you feel something was not addressed.