Bump bootstrap from 3.3.6 to 3.4.1

Bumps [bootstrap](https://github.com/twbs/bootstrap) from 3.3.6 to 3.4.1.
- [Release notes](https://github.com/twbs/bootstrap/releases)
- [Commits](twbs/bootstrap@v3.3.6...v3.4.1)

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

Author: dependabot[bot]

package-lock.json

@@ -22,7 +22,7 @@
     "gulp-less": "4.0.1"
   },
   "dependencies": {
-    "bootstrap": "3.3.6"
+    "bootstrap": "3.4.1"
   },
   "generated_theme": {
     "name": "Skeletal",