Feature request: allow to configure Changelog file regex

[arm4b]

First with GH star here! ⭐

Would be nice to have a changelog file regex configured.

For some repos it's possible to see CHANGELOG.md, some may rely on CHANGES.rst, CHANGELOG.rst and so on.

I'd say this is only missing feature to consume this Github Action in a wild.

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Also great idea with reminder to add a Changelog! I can finally automate this repeatable routine asking people to add a changelog record for every PR change they contribute.
Nit: Alternative way is to have this as CI check, as seen at https://github.com/marketplace/pr-milestone-check, but bot Comment is nice too.

[peterjgrainger]

Thanks @armab. As you can probably tell by the check, I made it for our specific use case :)

I was going to make it configurable but wanted to check that it was usable for someone else before I spent any more time on it and it is!

Should be straight forward to add an input but might make it a glob instead of regex.

If I don't get around to it I'll try to get a contributor in hacktoberfest