feat: support yml or yaml

[patrickleet]

This PR adds support for workflows in yaml or yml by checking which exists by name in getWorkflow rather than just setting it to yml.

Here's an example of it working on my fork: patrickleet#1

[patrickleet]

@peter-evans any feedback?

[peter-evans]

@patrickleet Thanks for contributing. Looked at it briefly and looks good to me. Good idea! Just trying to think about all the auth implications of this, but I think it's fine because the token used should already have access to the repository in order to create the dispatch. 🤔

I'm planning to get to this soon because I'll be making a new major version to support Node 24, anyway.

[patrickleet]

I made a versioning tool / workflow - just wrote a blog post about it recently: https://hackernoon.com/releasing-new-versions-should-be-boring-really-boring

Happy to make a PR to set up more automatic semantic versioning, separately, if that's something you'd be interested in