Fix Git permission issue during CI build

The new permissions checks to fix CVE-2022-29187 in Git caused some
issues in our CI pipeline. This patch fixes the owner of the git
checkout to be compliant with Git's new checks.

.github/workflows/linux-32bit-build-and-test.yaml

@@ -63,6 +63,9 @@ jobs:
 
     - name: Build TimescaleDB
       run: |
+        # Make sure that the Git checkout is fully owned by root (the active user). Otherwise
+        # git would complain about 'detected dubious ownership in repository'
+        chown root.root timescaledb -R
         ./bootstrap -DCMAKE_BUILD_TYPE="${{ matrix.build_type }}" -DPG_SOURCE_DIR=~/postgresql -DREQUIRE_ALL_TESTS=ON
         make -C build install
         chown -R postgres:postgres .