Feat: New Property athenz.zts.github_actions.prop_file_path for GitHubActionInstanceProvider

[mlajkim]

Description

You may use json file for multiple environment configuration as the following:

{
  "props": [
    {
      "provider_dns_suffix": "test-provider-suffix,another-test-provider-suffix",
      "enterprise": "test-enterprise",
      "audience": "test-audience",
      "issuer": "test-issuer",
      "jwks_uri": "https://test-jwks-uri.com/openid/v1/jwks"
    },
    {
      "provider_dns_suffix": "test-provider-suffix,another-test-provider-two-suffix",
      "enterprise": "test-enterprise-two",
      "audience": "test-audience-two",
      "issuer": "test-issuer-two",
      "jwks_uri": "https://test-jwks-uri-two.com/openid/v1/jwks"
    }
  ]
}

And set the following attribute:

athenz.zts.github_actions.prop_file_path=/path/to/file/for/the/config.json

Contribution Checklist:

• The pull request does not introduce any breaking changes
• I have read the contribution guidelines.
• Create an issue and link to the pull request.

Attach Screenshots (Optional)

[mlajkim]

Continues in #2992