Bump bootstrap from 3.3.7 to 3.4.1

Bumps [bootstrap](https://github.com/twbs/bootstrap) from 3.3.7 to 3.4.1.
- [Release notes](https://github.com/twbs/bootstrap/releases)
- [Commits](twbs/bootstrap@v3.3.7...v3.4.1)

---
updated-dependencies:
- dependency-name: bootstrap
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

package-lock.json

@@ -30,7 +30,7 @@
     "matchdep": "^1.0.0"
   },
   "dependencies": {
-    "bootstrap": "^3.2.0",
+    "bootstrap": "^3.4.1",
     "esri-leaflet": "^1.0.0",
     "jquery": "^1.11.1",
     "leaflet": "^0.7.7"