Add CA injection step for Docker Buildx in CI workflow

.gitea/workflows/ci.yaml

@@ -25,6 +25,11 @@ jobs:
             --username ${{ secrets.REGISTRY_USERNAME }} \
             --password-stdin
 
+      - name: Inject CA into buildkit
+        run: |
+          cat /etc/ssl/certs/homelab-ca.pem | docker exec -i buildx_buildkit_multiarch0 \
+            sh -c 'cat >> /etc/ssl/certs/ca-certificates.crt && cat >> /etc/ssl/cert.pem'
+
       - name: Set up Docker Buildx
         run: |
           docker buildx create --use --name multiarch || docker buildx use multiarch