Custom prefix, optional versioning based on multiple commit messages

[L-Sypniewski]

Added a possibility to use a custom prefix

Added a possibility to define an optional PREFIX parameter to be added before x.y.z version number.
Removed WITH_V parameter - omitting PREFIX results in the same behaviour as setting WITH_V to false in a previous versions.

Multiple commit messages are taken into account when bumping a version number

New version number is based on all commit messages between a defined commit (HEAD by default) and a last tag with a given prefix.
This behavior is disabled by default, it can be toggled on with USE_LAST_COMMIT_ONLY parameter set to false.

Added support for pull requests
Specifying latest branch commit is useful when using this action for pull requests - one can set environment variable as follows: BRANCH_LATEST_COMMIT: ${{ github.event.pull_request.head.sha }} to calculate a new version basing on commits from a given PR.

The x.y.z precedence is preserved, so if there are three commits with #minor tags and two with #major then only two #major tags are taken into consideration - the new version is (x+2).0.0 in that case.

Resolves #72
Resolves #226
Closes #95

[raphaelreyna]

Are there any plans on moving forward with this?
Adding custom prefixes would allow for this action to be used with Go submodules which would be pretty sweet 👍

[msummers-nr]

Will the custom prefix PR be accepted? Or some flavor of it?

I have a very pressing need to use a tag prefix other than v

Thanks

[sbe-arg]

Don't disagree with this but id probably warn some breaking changes in the readme for existing users not having the with_v var set and using default.

[L-Sypniewski]

@sbe-arg I have added the tests and resolved the conflicts, the PR is ready to be reviewed.
I'd appreciate suggestions especially regarding organizing the test related code - it think those tests are valuable, but they are hard to read.

@danrs #226 issue has been addressed and there's a testcase for it in this PR

[sbe-arg]

Thanks for sorting the conflicts.

We broke the flow for so many people in the last few prs specially related to history of commits. Adding the new last commit flags conflicts with the changes merged in the 1.61 1.60 and 1.59. Can you please remove the commits history and adjust it with the existing changes?

I do support the prefix idea I think is needed but I think it requires testing and is probably a great excuse for v2.

And thanks a million for the test scripts.

Cc @sammcj when you have time to have a look as well.

[sbe-arg]

We introduced the BRANCH_HISTORY setting in the last month

[sammcj]

What's happening with this one folks?

[sbe-arg]

I'm tempted to close this one and the author can reopen as necesary.