feat: non-chronological commits and commit body

[racinmat]

This PR addresses 2 issues that has been burning my team for quite some time already.

• if the commits are non-chronological, it was skipping them, which is fixed in this PR
• if commits were squashed, which often happens, and results in git commit with non-conventional name, it examines the body and searches for conventional commit messages there
• updates version to 1.1.0

The PR adds tests covering the new use-cases.

Convenience:

• the convbump is started by running the module, before the poetry script was needed, which made it tricky to run from PyCharm.

Fixes #26
Fixes #28