ci: update test runner to use ubuntu-latest

Signed-off-by: Paillat-dev <[email protected]>

Author: Paillat-dev

.github/workflows/lib-checks.yml

@@ -116,7 +116,7 @@ jobs:
       - name: "Run tests"
         run: uv run tox
   tests-pass: # ref: https://github.com/orgs/community/discussions/4324#discussioncomment-3477871
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-latest
     needs: [tests]
     if: ${{ github.event_name != 'schedule' }}
     steps: