Use github.event.repository.fork (#9551)

Author: hugovk

.github/workflows/stale.yml

@@ -17,7 +17,7 @@ env:
 
 jobs:
   stale:
-    if: github.repository_owner == 'python-pillow'
+    if: github.event.repository.fork == false
     permissions:
       issues: write
 

.github/workflows/wheels.yml

@@ -44,7 +44,7 @@ env:
 
 jobs:
   build-native-wheels:
-    if: github.event_name != 'schedule' || github.repository_owner == 'python-pillow'
+    if: github.event_name != 'schedule' || github.event.repository.fork == false
     name: ${{ matrix.name }}
     runs-on: ${{ matrix.os }}
     strategy:
@@ -136,7 +136,7 @@ jobs:
           path: ./wheelhouse/*.whl
 
   windows:
-    if: github.event_name != 'schedule' || github.repository_owner == 'python-pillow'
+    if: github.event_name != 'schedule' || github.event.repository.fork == false
     name: Windows ${{ matrix.cibw_arch }}
     runs-on: ${{ matrix.os }}
     strategy:
@@ -222,7 +222,7 @@ jobs:
           path: winbuild\build\bin\fribidi*
 
   sdist:
-    if: github.event_name != 'schedule' || github.repository_owner == 'python-pillow'
+    if: github.event_name != 'schedule' || github.event.repository.fork == false
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v6
@@ -260,7 +260,7 @@ jobs:
           [ "$files" -eq $EXPECTED_DISTS ] || exit 1
 
   scientific-python-nightly-wheels-publish:
-    if: github.repository_owner == 'python-pillow' && (github.event_name == 'schedule' || github.event_name == 'workflow_dispatch')
+    if: github.event.repository.fork == false && (github.event_name == 'schedule' || github.event_name == 'workflow_dispatch')
     needs: count-dists
     runs-on: ubuntu-latest
     name: Upload wheels to scientific-python-nightly-wheels
@@ -277,7 +277,7 @@ jobs:
           anaconda_nightly_upload_token: ${{ secrets.ANACONDA_ORG_UPLOAD_TOKEN }}
 
   pypi-publish:
-    if: github.repository_owner == 'python-pillow' && github.event_name == 'push' && startsWith(github.ref, 'refs/tags')
+    if: github.event.repository.fork == false && github.event_name == 'push' && startsWith(github.ref, 'refs/tags')
     needs: count-dists
     runs-on: ubuntu-latest
     name: Upload release to PyPI