Update update_operators.yml to allow automatic sync

[PProfizi]

This PR enacts changes on update_operators.yml to be called directly be the dpf_standalone PRs which will wait for the checks results.
This way the dpf-standalone PR actually properly tests updated client code based on the server modifications proposed in the dpf_standalone Windows PR.
Also, use of a PAT enables for automatic run of the checks upon PR creation, unlike the previous version.

[codecov]

Codecov Report

Merging #1312 (730deae) into master (6f8e75a) will decrease coverage by 1.25%.
The diff coverage is n/a.

❗ Current head 730deae differs from pull request most recent head 048a686. Consider uploading reports for the commit 048a686 to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1312      +/-   ##
==========================================
- Coverage   87.52%   86.28%   -1.25%     
==========================================
  Files          81       81              
  Lines        9243     9236       -7     
==========================================
- Hits         8090     7969     -121     
- Misses       1153     1267     +114     

[BClappe]

Instead of hardcoding '242', you can as well dynamically load a file at the beginning of the pipeline and assign a variable to hold the current value of the version. Thus you could have only one source of truth. But it's details.

[PProfizi]

What I'll eventually do is propagate from TFS the number of the last PR merged in DPF. I'll name the dpf-standalone PR and branch with this, and give it as input to this workflow to also name the PyDPF-Core PR and branch. That way instead of relying on something generic, we'll be able to know exactly which version of the server code we are synchronizing for. (That's the best way to know since we do not increment the server's version with a devX suffix)