ci(commit lint): ignore squash, fixup, revert

Related to #810 (closed)

This MR adds exceptions for the commit messages that can be used in MRs.

Exceptions:

• squash and fixup commits: https://github.com/conventional-changelog/commitlint/blob/master/%40commitlint/is-ignored/src/defaults.ts#L23
• reverts: https://github.com/conventional-changelog/commitlint/blob/master/%40commitlint/is-ignored/src/defaults.ts#L22