Release 2.0.0a2 - alpha quality, for testing only

borgbackup 2.0.0a2 alpha release - do not use this on production backup repositories.

Long changelog:
https://borgbackup.readthedocs.io/en/2.0.0a2/changes.html#version-2-0-0a2-2022-06-26

If you use pip to install this, use: pip install "borgbackup==2.0.0a2"

Docs: https://borgbackup.readthedocs.io/en/2.0.0a2/

Feedback:

• discussion: #6799