ci: use ubuntu-22.04 in test workflow

ubuntugis/ppa doesn't have a release for 24.04.

Author: danipran

.github/workflows/test.yml

@@ -12,7 +12,7 @@ on:
 jobs:
   test:
     name: Python ${{ matrix.python_version }}
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-22.04
     env:
       TOX_POSARGS: -- --cov=. --cov-report=xml
     strategy: