ci: use docker/setup-buildx-action to provide docker CLI

.gitea/workflows/ci.yml

@@ -64,9 +64,10 @@ jobs:
         with:
           fetch-depth: 0
 
+      - uses: docker/setup-buildx-action@v3
+
       - name: Pull changed images
         run: |
-          apt-get install -y docker.io -qq
           git fetch origin ${{ github.base_ref }}
           IMAGES=$(git diff origin/${{ github.base_ref }}...HEAD -- '*.nomad.hcl' \
             | grep '^+\s*image\s*=' \