Template main.yml workflow to enable feedback from tooling repo

[blakeNaccarato]

Dependabot runs over in blakeNaccarato/tooling. When a pull request is merged over there, I want the updated dependency to show up as a commit on this repo. That can be done by writing an update job into main.yml that needs all the other jobs in main.yml to succeed. Then, update will propagate changes back to blakeNaccarato/copier-python/template. This automates that section of the "loop" between the two repos.

The other end of the "loop", updating blakeNaccarato/tooling whenever the template changes, is less automatable. The questions/answers might change so the automation would be fragile. There is currently no way to not run a job if a certain file changes.

The update job shouldn't leak into my other projects, so it should be protected behind Jinja conditionals. That conditional could be tied to the gitignore_dependencies question which should probably be generalized to are_we_in_tooling or something.

Once this automation is established, it should become easier to maintain tooling, as bumped Dependencies will come as new commits.

[blakeNaccarato]

This is no longer necessary as all updates are either automatically handled here or manually propagated from blakeNaccarato/tooling.