revert compose / test.yml to py3.11

.github/workflows/test.yml

@@ -17,7 +17,7 @@ jobs:
       - name: Set up Python
         uses: actions/setup-python@v4
         with:
-          python-version: 3.13
+          python-version: 3.11
           cache: "pip"
       # Some mapfiles are generated by scripts, but also committed to the repo.
       # Check for mismatches between committed files and script output.

compose.yml

@@ -29,7 +29,7 @@ services:
 
   # Bare bones 'webserver' to behave as public loadbalancer
   publicdummy:
-    image: python:3.13-slim-bullseye
+    image: python:3.11-slim-bullseye
     ports:
       - 8000:8000
     command: python3 -m http.server 8000