CI: fix incorrect syntax

.github/workflows/build-docker.yml

@@ -5,20 +5,28 @@ on:
     paths-ignore: [ 'README.md' ]
 
 jobs:
-  test:
-    runs-on: python:3.12
-    steps:
-    - python -m pip install poetry
-    - poetry install
-    - poetry env info
-    - poetry run python manage.py migrate
-    - poetry run pytest
-  build-and-push:
+  checkout:
     runs-on: ubuntu-latest
-    if: github.ref == 'refs/heads/main'
     steps:
     - name: Checkout
       uses: actions/checkout@v4
+  test:
+    needs: checkout
+    runs-on: ubuntu-latest
+    container: python:3.12
+    steps:
+    - name: Run test
+      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:
     - name: Set up Docker Buildx
       uses: docker/setup-buildx-action@v3
     - name: Build and push