Removed dependency on String.js in accordance with https://nodesecuri… (#387)

* Removed dependency on String.js in accordance with https://nodesecurity.io/advisories/536

* only strip img tags

library.js

@@ -1,6 +1,6 @@
 'use strict';
 
-var S = require('string');
+var striptags = require('striptags');
 var meta = module.parent.require('./meta');
 var user = module.parent.require('./user');
 
@@ -29,7 +29,7 @@ library.addAdminNavigation = function(header, callback) {
 library.getTeasers = function(data, callback) {
 	data.teasers.forEach(function(teaser) {
 		if (teaser && teaser.content) {
-			teaser.content = S(teaser.content).stripTags('img').s;
+			teaser.content = striptags(teaser.content, ['img']);
 		}
 	});
 	callback(null, data);

package.json

@@ -39,6 +39,6 @@
     "url": "https://github.com/psychobunny/nodebb-theme-persona/issues"
   },
   "dependencies": {
-    "string": "^3.3.3"
+    "striptags": "^3.1.0"
   }
 }

yarn.lock

@@ -0,0 +1,7 @@
+# THIS IS AN AUTOGENERATED FILE. DO NOT EDIT THIS FILE DIRECTLY.
+# yarn lockfile v1
+
+
+striptags@^3.1.0:
+  version "3.1.0"
+  resolved "https://registry.yarnpkg.com/striptags/-/striptags-3.1.0.tgz#763e534338d9cf542f004a4b1eb099e32d295e44"