fix(fix-request-body): support '+json' content-type suffix

[howiezhao]

Description

Enhance fixRequestBody method to fix Content-Type includes +json

Motivation and Context

Now, if our Media Type includes +json but does not includes application/json, the fixRequestBody method will not work. For example, the Media Type is application/merge-patch+json.

According to RFC 6838, the + suffix indicates a structured type. Therefore, for the Media Type includes +json, we can directly serialize it to JSON.

This PR fixes the issue where the fixRequestBody method does not work for Media Types includes +json, such as application/merge-patch+json.

How has this been tested?

Unit Test

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist:

• My change requires a change to the documentation.
• I have updated the documentation accordingly.

[coveralls]

coverage: 97.686%. remained the same
when pulling aafb0bd on howiezhao:patch-1
into c8d34f1 on chimurai:master.

[coveralls]

coverage: 97.686%. remained the same
when pulling 830cbce on howiezhao:patch-1
into c8d34f1 on chimurai:master.

[chimurai]

Thank you so much for your time spent on this improvement; with detailed problem description, reference to RFC spec, creating the solution and accompanied by unit-tests.

This is how you do a PR! 🙏

Thanks @howiezhao!