ci: use python ubuntu image

Author: maciejmajek

.github/workflows/mkdocs-build.yml

@@ -11,9 +11,9 @@ jobs:
     if: github.event.pull_request.draft == false
 
     runs-on:
-      - python:3.12-slim
+      - ubuntu-latest
     container:
-      image: python:3.12-ubuntu
+      image: python:3.12-slim
 
     steps:
       - uses: actions/checkout@v4