[chore] add gogenerate makefile target

[codeboten]

Not sure why there wasn't a gogenerate yet, but this allows running generate for groups the way other go* makefile targets do.

[rogercoll]

CI error: doc.go:4: running "mdatagen": exec: "mdatagen": executable file not found in $PATH

Interestingly, the core repository installs the mdatagen tool into the GOPATH instead of the local .tools directory. I think that's the reason why the CI is failing. Should we install the tool in the GOPATH too or maybe just use relative paths to the mdatagen in the Go generate directives?

[github-actions[bot]]

This PR was marked stale due to lack of activity. It will be closed in 14 days.

[github-actions[bot]]

Closed as inactive. Feel free to reopen if this PR is still being worked on.