Merge pull request #1063 from owncloud/dependabot/npm_and_yarn/showdown-2.1.0

Bump showdown from 1.9.1 to 2.1.0

Author: DeepDiver1975

package-lock.json

@@ -39,7 +39,7 @@
     "npm-watch": "0.11.0",
     "pug": "3.0.1",
     "sass-loader": "6.0.7",
-    "showdown": "^1.9.1",
+    "showdown": "^2.1.0",
     "style-loader": "0.23.1",
     "uglify-js": "3.14.1",
     "uikit": "3.0.0-rc.26",