FEATURE REQUEST - Add "Tag Context"

[justin-newman]

Since this action was based off of the anothrNick/github-tag-action action, could we please get the TAG_CONTEXT input?

The current action will bump the version based exclusively on what the latest tag on the whole repo is, but some branches that are being used might be any number of major/minor versions behind and the action bumps the it way past where it should be if that's the case.

The description of this input from the "anothrNick" action reads: "TAG_CONTEXT (optional) - Set the context of the previous tag. Possible values are repo (default) or branch."