[CI] Use GitHub's own action to generate GitHub App token

[syl20bnr]

Attempt to fix the token creation error by switching to GitHub's own action.

[Luni-4]

Some tests are failing but this PR does not seem to be the cause

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 85.76%. Comparing base (040cd55) to head (5301020).
Report is 9 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1437      +/-   ##
==========================================
+ Coverage   85.71%   85.76%   +0.04%     
==========================================
  Files         639      640       +1     
  Lines       70543    70632      +89     
==========================================
+ Hits        60463    60574     +111     
+ Misses      10080    10058      -22     

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