fix: Refuse to push on pull_request event

[Kurt-von-Laven]

Avoid merging pull requests, which is unlikely to be the intended purpose of using this action.

Don't pull or push with nothing to push. Check whether there are any commits to push by comparing the project version before and after bumping.

Print error message to stderr.

Fixes #29.

[woile]

I think this is a great addition, but we also cannot predict what people use this action for. I like having this as the default behavior, but could you add a setting to override it? Thanks!

[Kurt-von-Laven]

Thank you for the feedback; I added a merge input that allows the new default behavior to be overridden. Let me know if a different parameter name would be preferable.

[woile]

Fantastic, I would make it true by default. Just to be clear I think this is a good check. I'm just worried if someone is already using it in a different way, that's why I would like to have the option to skip it. But specially for newcomers I think it should be on by default 👍🏻 thanks again!

[Kurt-von-Laven]

If I make the default value of merge true, I believe that would turn this feature off by default, retaining the existing behavior unless false is explicitly passed.

[woile]

Oh sorry, didn't read properly. Let mergee 🎉