Detect commit messages in the squashed commit

[bahmutov]

For example see https://github.com/bahmutov/generator-node-bahmutov/commit/8eb48addc834294f6248d163e69c37ef3ca38e12

The subject is just Immutable (#57) but the body has titles from 3 commits that were squashed from the pull request. One of them is semantic commit! Should detect such commits and return valid list

* feat(immutable): optional immutable linter, close #56

* add immutable to E2E answers

* add note to readme

[yurist38]

➕ Vote for it! Would be really nice to get it done!