fix: add missing build context and --push flag to CI base image workflow

The docker build command was missing the build context path (.) and
the --push flag to actually push to the registry after building.

.gitea/workflows/build-ci-images.yml

@@ -52,12 +52,13 @@ jobs:
 
       - name: Build and push CI base image
         run: |
-          # Build with multiple tags
           docker build \
             --file Dockerfile.ci-base \
             --tag ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}/ci-base:latest \
             --tag ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}/ci-base:playwright-${{ steps.meta.outputs.playwright_version }} \
             --tag ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}/ci-base:${{ github.sha }} \
+            --push \
+            .
 
       - name: Clean up
         if: always()