Release 7.0.0a5

Release 7.0.0a4

[IMPR] Removed poetry from thumbor

**Is backwards compatible**: yes

This commit removes poetry from thumbor as it was making it
increasingy harder to release consistent versions.

We still manage to keep most of the versioning used in poetry in
setup.py. If you feel like the versions can be a little looser, just PR.

Fixed flake

Release 6.7.4

Release 6.7.3

Release 7.0.0a2

Release 7.0.0a1

[RELEASE] Release 6.7.2

Release 6.7.1