Fix git push conflict in iOS workflow

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: utsapoddar

.github/workflows/build-ios.yml

@@ -75,4 +75,4 @@ jobs:
           git config user.name "github-actions[bot]"
           git add altstore-source.json
           git diff --staged --quiet || git commit -m "chore: update AltStore source to v$VERSION [skip ci]"
-          git push
+          git pull --rebase && git push