CI: pin back pygobject

Author: tacaswell

.github/workflows/tests.yml

@@ -79,6 +79,8 @@ jobs:
             python-version: '3.12'
           - os: macos-14  # This runner is on M1 (arm64) chips.
             python-version: '3.11'
+            # https://github.com/matplotlib/matplotlib/issues/29732
+            pygobject-ver: '<3.52.0'
           - os: macos-14  # This runner is on M1 (arm64) chips.
             python-version: '3.12'
             # https://github.com/matplotlib/matplotlib/issues/29732