auto-deploy GHA workflow

[orbeckst]

• use MDAnalysis/pypi-deployment action for automatic deployment
• external: enable trusted publishing on PyPi and TestPyPi

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 81.65%. Comparing base (dd787f7) to head (3a838fb). Report is 1 commits behind head on develop.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## develop #292 +/- ## ======================================== Coverage 81.65% 81.65% ======================================== Files 15 15 Lines 2017 2017 Branches 310 310 ======================================== Hits 1647 1647 Misses 275 275 Partials 95 95 ```

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.