Add disk space cleanup to E2E tests workflow

GitHub runners have limited disk space (~14GB free). E2E tests build multiple
Docker images which can fill up the disk, causing "no space left on device"
errors.

Free up ~10GB by removing unused packages (.NET, Android SDK, GHC) and
cleaning Docker at the start of the workflow, before the kind cluster is
created. This cleanup is safe because it runs before any test infrastructure
exists.

Author: creydr

.github/workflows/test-e2e.yml

@@ -19,6 +19,14 @@ jobs:
         builder: [pack, s2i]
         deployer: [knative, raw, keda]
     steps:
+      - name: Free up disk space
+        run: |
+          # Remove large packages to free up disk space on GitHub runners
+          sudo rm -rf /usr/share/dotnet /usr/local/lib/android /opt/ghc
+          # Clean up Docker to start fresh
+          docker system prune -af --volumes
+          df -h
+
       - name: Clone the code
         uses: actions/checkout@v6