chore: update default Python version to 3.10

[jansegre]

Also adds necessary tweaks to get it working with PyPy.

Motivation

For a while we've supported Python 3.9, 3.10 and 3.11, but the default has been stuck on 3.9, even though it's been running smoothly on 3.10 and 3.11 which have performance benefits.

Acceptance Criteria

• Bump the default version for the docker image from Python 3.9 to Python 3.10
• Update PyYaml version from 6.0.0 to 6.0.1 so it installs correctly on the PyPy docker image
• Update the Docker build script to include Python 3.10 compatibility for PyPy

Checklist

• If you are requesting a merge into master, confirm this code is production-ready and can be included in future releases as soon as it gets merged

[codecov]

Codecov Report

Merging #712 (5c04547) into master (b826588) will decrease coverage by 0.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #712      +/-   ##
==========================================
- Coverage   84.00%   84.00%   -0.01%     
==========================================
  Files         247      247              
  Lines       20625    20625              
  Branches     2784     2784              
==========================================
- Hits        17327    17326       -1     
  Misses       2719     2719              
- Partials      579      580       +1     

see 2 files with indirect coverage changes