Add support for go workspace

[spacecowboy]

Thanks for stopping by to let us know something could be better!

Is your feature request related to a problem? Please describe.

When developing go modules in a monorepo, it would be nice to update versions transitively when changes happen in dependent libraries.

Describe the solution you'd like

release-please should parse a go.work file in the root folder in the same way that cargo-workspace or node-workspace works.

Describe alternatives you've considered

Did consider non-standard solutions but that is not as good.

Additional context

Will be opening a PR that implements this feature in a moment