[build] Check if mapbox-gl-js is pinned to master

circle.yml

@@ -666,6 +666,10 @@ jobs:
             scripts/generate-shaders.js
             scripts/generate-style-code.js
             git add -A && git diff --staged --exit-code
+      - run:
+          name: Validation Scripts
+          command: |
+            scripts/nitpick/submodule-pin.js
       - run:
           name: CMake Format
           command: |