Adds a pyproject file.

[arokem]

I would like to see whether the issues we are seeing in tee-ar-ex/trx-python#57 are mitigated through the addition of a pyproject file.

[codecov]

Codecov Report

Merging #2787 (11a94c0) into master (8091b0a) will increase coverage by 0.40%.
The diff coverage is n/a.

❗ Current head 11a94c0 differs from pull request most recent head 55f9588. Consider uploading reports for the commit 55f9588 to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2787      +/-   ##
==========================================
+ Coverage   81.41%   81.81%   +0.40%     
==========================================
  Files         145      144       -1     
  Lines       20147    19694     -453     
  Branches     3217     3142      -75     
==========================================
- Hits        16402    16112     -290     
+ Misses       2929     2807     -122     
+ Partials      816      775      -41     

see 33 files with indirect coverage changes

[skoudoro]

superseded by #2759 and #2715

closing