Merge pull request #5043 from plotly/prepend-file-2.0.0

bump prepend-file v2

Author: archmoj

package-lock.json

@@ -162,7 +162,7 @@
     "node-sass": "^4.14.1",
     "npm-link-check": "^4.0.0",
     "open": "^7.1.0",
-    "prepend-file": "^1.3.1",
+    "prepend-file": "^2.0.0",
     "prettysize": "^2.0.0",
     "read-last-lines": "^1.7.2",
     "requirejs": "^2.3.6",