Fix HEAD fails on branch alias for build integration jobs

Author: mglaman

.github/workflows/php.yml

@@ -89,10 +89,18 @@ jobs:
         with:
           version: ${{ matrix.drupal }}
           path: ~/drupal
+      - name: "set the version alias for self"
+        run: |
+          if [ "${{ github.event_name }}" == 'pull_request' ]; then
+            echo ::set-output name=VERSION_ALIAS::dev-"${{ github.sha }}"
+          else
+            echo ::set-output name=VERSION_ALIAS::dev-main
+          fi
+        id: branch_alias
       - name: "require phpstan-drupal"
         run: |
           cd ~/drupal
-          COMPOSER_MEMORY_LIMIT=-1 composer require mglaman/phpstan-drupal "dev-${{ github.sha }} as 1.1.99" phpstan/extension-installer --with-all-dependencies
+          COMPOSER_MEMORY_LIMIT=-1 composer require mglaman/phpstan-drupal "${{ steps.branch_alias.outputs.VERSION_ALIAS }} as 1.1.99" phpstan/extension-installer --with-all-dependencies
           cp $GITHUB_WORKSPACE/tests/fixtures/config/drupal-phpstan.neon phpstan.neon
       - name: "Test core/install.php"
         run: |