The system test configuration is expressed as YAML and many other package files are also expressed as YAML. However, pipeline test configuration files (example: https://github.com/elastic/package-spec/blob/master/code/go/internal/validator/test/packages/good/data_stream/foo/_dev/test/pipeline/test-access-raw.log-config.json) is expressed as JSON. Should we change this to be YAML as well?

Rollout plan for this change

• Enhance package spec to allow *.yml pipeline test configuration files in addition to the currently-allowed *.json ones. Mark the *.json file format as deprecated (exactly how to do this is TBD). This will give package authors some time to adjust their pipeline test configuration file formats: Deprecating JSON-formatted pipeline test configs in favor of YAML-formatted ones #139.
• Update all pipeline test configuration files in the integrations repo from *.json => *.yml: Replacing .json pipeline test config files with .yml ones integrations#739.
• Notify package stakeholders that *.json pipeline test configuration files are being removed and replaced by *.yml ones.
• After a few weeks:
  • Notify package stakeholders that support for *.json pipeline test configuration files is being removed.
  • Remove support for *.json pipeline test configuration files from package spec: Remove pipeline test config json #150.
  • Notify package stakeholders that support for *.json pipeline test configuration files has been removed.