CI: fix incorrect syntax

.github/workflows/build-docker.yml

@@ -0,0 +1,36 @@
+name: Django CI/CD
+
+on:
+  push:
+    paths-ignore: [ 'README.md' ]
+
+jobs:
+  test:
+    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:
+    runs-on: ubuntu-latest
+    if: github.ref == 'refs/heads/main'
+    steps:
+    - name: Checkout
+      uses: actions/checkout@v4
+    - name: Set up Docker Buildx
+      uses: docker/setup-buildx-action@v3
+    - name: Build and push
+      uses: docker/build-push-action@v5
+      with:
+        context: .
+        push: true
+        tags: |
+          registry.kucharczyk.xyz/timetracker:latest
+          registry.kucharczyk.xyz/timetracker:${{ env.VERSION_NUMBER }}          
+    env:
+      VERSION_NUMBER: 1.5.1