Fix travis

.travis.yml

@@ -7,6 +7,6 @@ addons:
   chrome: stable
 node_js:
  - "10"
-install: make stamp-npm
+install: make node_modules
 before_script: make serve_bg
 script: make check

package.json

@@ -20,7 +20,7 @@
   ],
   "scripts": {
     "serve": "webpack-dev-server --config webpack.serve.js",
-    "clean": "rm -rf node_modules stamp-npm dist *.zip",
+    "clean": "rm -rf node_modules dist *.zip",
     "headless": "webpack --config webpack.headless.js",
     "nodeps": "webpack --config webpack.nodeps.js",
     "cdn": "ASSET_PATH=https://cdn.conversejs.org/dist/ npm run dev && ASSET_PATH=https://cdn.conversejs.org/dist/ npm run build",