Temporarily pin Ubuntu CI version to 22.04, since 24.04 causes regression. (#513)

Signed-off-by: Steffen Smolka <[email protected]>

Author: smolkaj

.github/workflows/ci-build-proto.yml

@@ -14,7 +14,7 @@ on:
 
 jobs:
   build:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-22.04
     env:
       BAZEL: bazelisk-linux-amd64
     steps: