CI: fix incorrect syntax

.github/workflows/build-docker.yml

@@ -6,14 +6,20 @@ on:
 
 jobs:
   test:
-    runs-on: python:3.12
+    runs-on: ubuntu-latest
     steps:
-    - python -m pip install poetry
-    - poetry install
-    - poetry env info
-    - poetry run python manage.py migrate
-    - poetry run pytest
+      - uses: actions/checkout@v4
+      - uses: actions/setup-python@v4
+        with:
+          python-version: 3.12
+      - run: |
+          python -m pip install poetry
+          poetry install
+          poetry env info
+          poetry run python manage.py migrate
+          poetry run pytest
   build-and-push:
+    needs: test
     runs-on: ubuntu-latest
     if: github.ref == 'refs/heads/main'
     steps: