Handle reverting commits

[bennycode]

GitHub has the functionality to revert a Pull Request. In this case an automatic PR title will be generted. This title has the format of: Revert "the original commit message". It would be cool if "generate-changelog" removes the original commit message from the log if a reverting commit is found afterwards. 😀

Example commit message:

chore(deps): Bump @types/generate-changelog from 1.8.0 to 1.8.1

Reverting commit message:

Revert "chore(deps): Bump @types/generate-changelog from 1.8.0 to 1.8.1"