Only apply fixes for PRs

.github/workflows/build.yml

@@ -24,36 +24,26 @@ concurrency:
   cancel-in-progress: true
 
 jobs:
-  get_ci_fixes:
+  build:
     runs-on: ubuntu-latest
+    container: ghcr.io/sagemath/sage/sage-${{ github.event.inputs.platform || 'ubuntu-focal-standard' }}-with-targets:${{ github.event.inputs.docker_tag || 'dev'}}
     steps:
       - name: Checkout
         id: checkout
         uses: actions/checkout@v4
+
+      - name: Install GH CLI
+        uses: dev-hanz-ops/[email protected]
+        if: ${{ github.event_name == 'pull_request' }}
+        with:
+          gh-cli-version: 2.32.0
+
       - name: Merge CI fixes from sagemath/sage
+        if: ${{ github.event_name == 'pull_request' }}
         run: |
           .ci/merge-fixes.sh
         env:
           GH_TOKEN: ${{ github.token }}
-      - name: Store CI fixes in upstream artifact
-        run: |
-          mkdir -p upstream
-          if git format-patch --stdout test_base > ci_fixes.patch; then
-            cp ci_fixes.patch upstream/
-          fi
-      - uses: actions/upload-artifact@v3
-        with:
-          path: upstream
-          name: upstream
-
-  build:
-    runs-on: ubuntu-latest
-    container: ghcr.io/sagemath/sage/sage-${{ github.event.inputs.platform || 'ubuntu-focal-standard' }}-with-targets:${{ github.event.inputs.docker_tag || 'dev'}}
-    needs: [get_ci_fixes]
-    steps:
-      - name: Checkout
-        id: checkout
-        uses: actions/checkout@v4
 
       - name: Update system packages
         id: prepare