CI/AppImage: Work around GH runner issue 8659

.github/workflows/rolling-release.yml

@@ -204,6 +204,14 @@ jobs:
   linux-build:
     runs-on: ubuntu-22.04
     steps:
+    # Work around https://github.com/actions/runner-images/issues/8659
+    - name: Remove GCC 13 from runner image
+      shell: bash
+      run: |
+        sudo rm -f /etc/apt/sources.list.d/ubuntu-toolchain-r-ubuntu-test-jammy.list
+        sudo apt-get update
+        sudo apt-get install -y --allow-downgrades libc6=2.35-0ubuntu3.4 libc6-dev=2.35-0ubuntu3.4 libstdc++6=12.3.0-1ubuntu1~22.04 libgcc-s1=12.3.0-1ubuntu1~22.04
+
     - uses: actions/checkout@v2.3.1
       with:
         fetch-depth: 0