github/workflow: enable MQTT in the macOS debug build
diff --git a/.github/workflows/macos.yml b/.github/workflows/macos.yml
index 6910b9c..666c499 100644
--- a/.github/workflows/macos.yml
+++ b/.github/workflows/macos.yml
@@ -23,7 +23,7 @@
           install: nghttp2
         - name: debug
           install: nghttp2
-          configure: --enable-debug --enable-werror --without-brotli
+          configure: --enable-debug --enable-werror --without-brotli --enable-mqtt
         - name: libssh2
           install: nghttp2 libssh2
           configure: --enable-debug --with-libssh2