ci: don't run PR job on main

[agoose77]

---

📚 The documentation for this PR will be available at https://awkward-array.readthedocs.io/en/agoose77-ci-fix-deploy-main/ once Read the Docs has finished building 🔨

[agoose77]

I missed something in the last PR (note-to-self, when you assume, you make an ass out of u and me). This fixes the last approved PR, so I'm happy to merge without a second pair of eyes.

[codecov]

Codecov Report

Merging #1853 (a0da7a1) into main (a7e4ef6) will decrease coverage by 0.01%.
The diff coverage is n/a.

Additional details and impacted files

Impacted Files	Coverage Δ
src/awkward/contents/indexedarray.py	76.60% <0.00%> (-0.19%)	⬇️
src/awkward/contents/recordarray.py	83.87% <0.00%> (-0.19%)	⬇️
src/awkward/_util.py	82.21% <0.00%> (-0.18%)	⬇️
src/awkward/contents/indexedoptionarray.py	88.90% <0.00%> (-0.16%)	⬇️
src/awkward/_connect/avro.py	87.17% <0.00%> (-0.14%)	⬇️
src/awkward/types/_awkward_datashape_parser.py	47.72% <0.00%> (-0.01%)	⬇️

[jpivarski]

Yes, that's fine. Some of these I review as, "I don't know how the docs/CI system works, but I can see that the output is right." I had thought that the qualifier for the last one was that the docs were generated.

[agoose77]

Looks like it succeeded (at least the build triggers!)