feat/adding preppost license to allowed

[germa89]

Description

Add "preppost" license to allowed.

Issue linked

Close #3284

Checklist

• I have visited and read Develop PyMAPDL.
• I have tested my changes locally
• I have added necessary documentation or updated existing documentation.
• I have followed the PyMAPDL coding style guidelines.
• I have added appropriate unit tests that also ensure the minimal coverage criteria.
• I have reviewed my changes before submitting this pull request.
• I have linked the issue or issues that are solved to the PR if any.
• I have assigned this PR to myself.
• I have marked this PR as draft if it is not ready to be reviewed yet.
• I have made sure that the title of my PR follows Commit naming conventions (e.g. feat: adding new MAPDL command)

[ansys-reviewer-bot]

Thanks for opening a Pull Request. If you want to perform a review write a comment saying:

@ansys-reviewer-bot review

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 87.16%. Comparing base (93dd176) to head (d7a6e85).
Report is 6 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3294      +/-   ##
==========================================
+ Coverage   87.13%   87.16%   +0.03%     
==========================================
  Files          55       55              
  Lines        9816     9818       +2     
==========================================
+ Hits         8553     8558       +5     
+ Misses       1263     1260       -3     

[germa89]

@pyansys-ci-bot LGTM.

[pyansys-ci-bot]

✅ Approving this PR because germa89 said so in here 😬