Bump markdown-it from 8.4.1 to 8.4.2 in /js

Bumps [markdown-it](https://github.com/markdown-it/markdown-it) from 8.4.1 to 8.4.2.
- [Release notes](https://github.com/markdown-it/markdown-it/releases)
- [Changelog](https://github.com/markdown-it/markdown-it/blob/master/CHANGELOG.md)
- [Commits](https://github.com/markdown-it/markdown-it/compare/8.4.1...8.4.2)

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

js/package.json

@@ -15,7 +15,7 @@
     "angular-markdown-it": "^0.6.1",
     "angular-sanitize": "^1.7.2",
     "babel-polyfill": "^6.26.0",
-    "markdown-it": "^8.4.1",
+    "markdown-it": "^8.4.2",
     "markdown-it-link-target": "^1.0.2",
     "ng-sortable": "^1.3.8",
     "ui-select": "^0.19.8"