Explicitly pull docker images

This is due to a change in constellation 1.2.3 - see vimc/orderly-web-deploy#56
for an analogous fix

Author: david-mears-2

.github/workflows/test.yml

@@ -29,6 +29,15 @@ jobs:
         uses: actions/setup-python@v5
         with:
           python-version: ${{ matrix.python-version }}
+      - name: Pull containers
+        run: |
+          docker pull redis:5.0
+          docker pull mrcide/outpack.orderly:main
+          docker pull mrcide/outpack_server:main
+          docker pull mrcide/packit-db:main
+          docker pull mrcide/packit-api:main
+          docker pull mrcide/packit:main
+          docker pull mrcide/packit-proxy:main
       - name: Install dependencies
         run: |
           python -m pip install --upgrade pip