InnerSource Contributions labeler #96

New Action request

Description

It would be helpful to be able to label contributions to a project that come from outside the owning team. This is beneficial for being able to recognize InnerSource practices and measure statistics related to that. This action could be combined with the issue-metrics action to get those statistics for issues/and PRs labeled as InnerSource. InnerSource in this case would be defined as contributions from a non-owner team within an organization. ie. When a feature team contributes to the observability tools on which they depend but do not own as an area of responsibility.

Additionally it may be helpful to "label" the repository with a Repository Topic so that it can be identified as a repository that practices InnerSource.

One complication that would need to be overcome here is the method by which a contribution is determined to be from a "non-owner" team. The tool could rely on several places to get ownership information:

• Interface with Backstage API assuming that there is a Backstage instance that has a complete catalog of repos with ownership information
• Codeowners file (If someone or a group they belong to is in the codeowners file then they could be considered an owner)
• An org chart interface (API) (such as workday, etc.)
• Other ideas? Open to thoughts here...