added cd before make

Author: Reinhold Willcox

.github/workflows/compas-compile-ci.yml

@@ -13,4 +13,4 @@ jobs:
       - uses: actions/checkout@v2
 
       - name: Build Compas
-        run: make -j $(nproc) -f src/Makefile
+        run: cd src && make -j $(nproc) -f Makefile