ci: install docker CLI static binary instead of setup-buildx-action

.gitea/workflows/ci.yml

@@ -64,10 +64,10 @@ jobs:
         with:
           fetch-depth: 0
 
-      - uses: docker/setup-buildx-action@v3
-
       - name: Pull changed images
         run: |
+          curl -fsSL https://download.docker.com/linux/static/stable/x86_64/docker-27.5.1.tgz \
+            | tar -xz --strip-components=1 -C /usr/local/bin docker/docker
           git fetch origin ${{ github.base_ref }}
           IMAGES=$(git diff origin/${{ github.base_ref }}...HEAD -- '*.nomad.hcl' \
             | grep '^+\s*image\s*=' \