Bump jquery from 1.12.4 to 3.4.1

Bumps [jquery](https://github.com/jquery/jquery) from 1.12.4 to 3.4.1.
- [Release notes](https://github.com/jquery/jquery/releases)
- [Commits](https://github.com/jquery/jquery/compare/1.12.4...3.4.1)

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

package.json

@@ -34,7 +34,7 @@
     "gulp-sass": "4.0.2",
     "gulp-uglify": "3.0.2",
     "hogan": "1.0.2",
-    "jquery": "1.12.4",
+    "jquery": "3.4.1",
     "query-command-supported": "1.0.0",
     "textarea-caret": "3.1.0",
     "timeago": "1.6.5"