Merge pull request #471 from morpho-org/ci/forge-build-locked

[ci] check foundry.lock matches submodule pins

Author: QGarchery

.github/workflows/foundry.yml

@@ -28,6 +28,9 @@ jobs:
       - name: Build contracts & check sizes
         run: forge build --force --sizes # don't use compilation cache
 
+      - name: Check foundry.lock matches submodule pins
+        run: forge build --locked
+
   test:
     needs: build