Bump tinymce from 5.1.2 to 5.1.3

Bumps [tinymce](https://github.com/tinymce/tinymce-dist) from 5.1.2 to 5.1.3.
- [Release notes](https://github.com/tinymce/tinymce-dist/releases)
- [Changelog](https://github.com/tinymce/tinymce-dist/blob/master/changelog.txt)
- [Commits](https://github.com/tinymce/tinymce-dist/compare/5.1.2...5.1.3)

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

package-lock.json

       }
     },
     "tinymce": {
-      "version": "5.1.2",
-      "resolved": "https://registry.npmjs.org/tinymce/-/tinymce-5.1.2.tgz",
-      "integrity": "sha512-P61Odc3O2IDvC1qBmd7xkh1uRDKtfn8YNvh3sone84H9/W527HNbATbXpin/ewzZHxhw67hKRe9FzOBhQzFQig==",
+      "version": "5.1.3",
+      "resolved": "https://registry.npmjs.org/tinymce/-/tinymce-5.1.3.tgz",
+      "integrity": "sha512-l3gE5dVU7S07ayGm+gZSrH7wQM4QJ3RZhjzv6iFOY2OdIFJ/saD9JMZcNmgX/IsZfBdTqhd0OLnTS8uMfHN+TA==",
       "dev": true
     },
     "tmp": {

package.json

     "pump": "^3.0.0",
     "select2": "4.0.12",
     "select2-bootstrap-theme": "0.1.0-beta.10",
-    "tinymce": "^5.1.2"
+    "tinymce": "^5.1.3"
   },
   "scripts": {
     "build": "gulp copy && gulp less",