no type checking on old Ubuntu 18

diff --git a/.github/workflows/ci-tests.yml b/.github/workflows/ci-tests.yml
index 7dffe7bbc70e6c1453d21cf6ef48cebdeacfd0a4..35e6306a7830b3b6e55ddec044aedc63885899e5 100644 (file)
--- a/.github/workflows/ci-tests.yml
+++ b/.github/workflows/ci-tests.yml
@@ -129,10 +129,12 @@ jobs:
 
             - name: Install newer Python packages (for typechecking info)
               run: pip3 install -U osmium uvicorn
+              if: matrix.ubuntu >= 20
 
             - name: Python static typechecking
               run: python3 -m mypy --strict nominatim
               working-directory: Nominatim
+              if: matrix.ubuntu >= 20
 
     legacy-test:
         needs: create-archive