add PRs into main as pypi.yml trigger for testing the local wheel build

Author: akeeste

.github/workflows/pypi.yml

@@ -7,6 +7,9 @@ on:
   push:
     branches:
       - main
+  pull_request:
+    branches:
+      - main
   release:
     types: [published]
 
@@ -36,8 +39,8 @@ jobs:
           pip install 'mhkit[all]' --find-links dist/
           python -c "from mhkit import wave, river, tidal, dolfyn, power, loads, mooring, acoustics, qc, utils; print('All modules imported successfully')"
 
-      - name: Upload to Test PyPI
-        if: github.event_name != 'release' && github.repository_owner == 'MHKiT-Software'
+      - name: Upload to Test PyPI (commits to main only)
+        if: github.event_name == 'push' && github.repository_owner == 'MHKiT-Software'
         uses: pypa/gh-action-pypi-publish@release/v1
         with:
           user: __token__