fix warning related with bootstrap missing dependencies

closes #119

Author: enriquezrene

package-lock.json

@@ -63,7 +63,8 @@
     "semantic-release": "^17.0.4",
     "ts-node": "~8.3.0",
     "tslint": "~5.18.0",
-    "typescript": "~3.7.5"
+    "typescript": "~3.7.5",
+    "popper.js": "^1.16.0"
   },
   "husky": {
     "hooks": {