fixup! Update GitHub CI run image

Author: findepi

.github/workflows/rust.yml

@@ -389,7 +389,7 @@ jobs:
   test-datafusion-pyarrow:
     name: cargo test pyarrow (amd64)
     needs: linux-build-lib
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     container:
       image: amd64/rust:bullseye # Workaround https://github.com/actions/setup-python/issues/721
     steps: