Pin to "4.0.0" not "v4.0.0"

Author: thallada

package.json

@@ -14,7 +14,7 @@
   ],
   "homepage": "https://github.com/edx/edx-bootstrap#readme",
   "dependencies": {
-    "bootstrap": "v4.0.0",
+    "bootstrap": "4.0.0",
     "jquery": "^3.2.1",
     "popper.js": "^1.12.6"
   },