Check for GitHub dependencies on Travis.

RubenVerborgh · RubenVerborgh · commit 8b934f7ada86 · 2018-09-29T21:30:22.000+02:00
diff --git a/.travis.yml b/.travis.yml
@@ -12,6 +12,8 @@ addons:
     - nicola.localhost
 
 before_install:
+  - echo "No GitHub dependencies allowed" &&
+    ! grep '"github:' package-lock.json
   - npm install -g npm@latest
 
 install:
