Build the correct image (#308)

Oops. #307 introduced the xmtpd-cli docker image but it actually ended
up being xmtpd.
Fix it.

.github/workflows/build-xmtpd.yml

@@ -43,13 +43,23 @@ jobs:
             type=ref,event=tag
             type=ref,event=pr
             type=sha
-
+      - name: Set up Docker image file based on the matrix variable
+        id: set_dockerfile
+        run: |
+          if [[ "${{ matrix.image }}" == "xmtpd" ]]; then
+          echo "dockerfile=Dockerfile" >> $GITHUB_OUTPUT
+          elif [[ "${{ matrix.image }}" == "xmtpd-cli" ]]; then
+          echo "dockerfile=Dockerfile-cli" >> $GITHUB_OUTPUT
+          else
+          echo "Unknown image: ${{ matrix.image }}"
+          exit 1
+          fi
       - name: Build and push Docker image
         uses: docker/build-push-action@v6
         id: push
         with:
           context: .
-          file: ./dev/docker/Dockerfile
+          file: ./dev/docker/${{ steps.set_dockerfile.outputs.dockerfile }}
           push: ${{ github.event_name != 'pull_request' }}
           tags: ${{ steps.meta.outputs.tags }}
           labels: ${{ steps.meta.outputs.labels }}