fix(ci): add pull-requests write permission to update workflow

[yfodil]

Description of your changes

Fixes #

I have:

• Read and followed Crossplane's contribution process.
• Run make reviewable test to ensure this PR is ready for review.

How has this code been tested

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 0.00%. Comparing base (adcdedf) to head (f94441e).
⚠️ Report is 2 commits behind head on main.

Additional details and impacted files

@@          Coverage Diff          @@
##            main    #197   +/-   ##
=====================================
  Coverage   0.00%   0.00%           
=====================================
  Files        476     476           
  Lines      60567   60567           
=====================================
  Misses     60567   60567           

Flag	Coverage Δ
unittests	0.00% <ø> (ø)

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