Options to include/exclude tags

[pawamoy]

Is your feature request related to a problem? Please describe.
Alpha, beta, and release candidate tags are generally left out of changelogs once the actual version is released.

Describe the solution you'd like
Mutually exclusive options to include or exclude tags when parsing commits, using regular expressions.

Describe alternatives you've considered
Tinkering with a Changelog instance and its versions list and dict. Not practical.

[PvtPuddles]

I have an additional related issue that would also be resolved by tag RegEx.

Our project is a mono-repo with multiple separately versioned projects in the same git directory. The tags are formatted like [Product code]-[SemVar]. Being able to filter by product code would allow us to continue maintaining separate changelings for separate products. Combined with #90, git-changelog would be a very powerful tool for us.