Remove PR creation from release job.

[ouphi]

What is being addressed

We are not allowed anymore to have PR creation done from Github action:

Because of that the release job fails when trying to create the PR:

How is this addressed

Change the release process:

• The release job will be creating branches instead and the developer taking care of the release has to create the PRs.

[codecov-commenter]

Codecov Report

Merging #2109 (ecb1e9f) into dev (c32ecd8) will decrease coverage by 0.04%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##              dev    #2109      +/-   ##
==========================================
- Coverage   83.00%   82.97%   -0.04%     
==========================================
  Files         256      256              
  Lines        9309     9309              
  Branches     1455     1455              
==========================================
- Hits         7727     7724       -3     
- Misses       1138     1140       +2     
- Partials      444      445       +1     

see 2 files with indirect coverage changes