[sdk/go] Check for pulumiplugin.json in GetRequiredPlugins

[iwahbe]

Description

Checks for pulumiplugin.json in Dir (from go list -m -json -mod=mod all).

Fixes #7245

Checklist

• I have added tests that prove my fix is effective or that my feature works

• I have updated the CHANGELOG-PENDING file with my change

• Yes, there are changes in this PR that warrants bumping the Pulumi Service API version

[pgavlin]

Have we validated that the module sources always include all of the files present in the module's repo? I'm wondering if we need to update our Go codegen to ensure that the pulumiplugin.json file is referenced from the code via a //go:embed directive or similar.

[iwahbe]

Have we validated that the module sources always include all of the files present in the module's repo? I'm wondering if we need to update our Go codegen to ensure that the pulumiplugin.json file is referenced from the code via a //go:embed directive or similar.

Our codegen does not currently include pulumiplugin.json at all for go. That will be added in another PR. Performing a quick test, it seems like files are just included. It doesn't seem like we need to include a //go:embed directive.

[justinvp]

LGTM. I've also verified that pulumiplugin.json file is included in the module.