Bump tinymce from 5.8.2 to 5.9.1

Bumps [tinymce](https://github.com/tinymce/tinymce/tree/HEAD/modules/tinymce) from 5.8.2 to 5.9.1.
- [Release notes](https://github.com/tinymce/tinymce/releases)
- [Changelog](https://github.com/tinymce/tinymce/blob/develop/modules/tinymce/CHANGELOG.md)
- [Commits](https://github.com/tinymce/tinymce/commits/5.9.1/modules/tinymce)

---
updated-dependencies:
- dependency-name: tinymce
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

package-lock.json

@@ -59,6 +59,6 @@
         "source-sans-pro": "^3.6",
         "summernote": "^0.8.18",
         "sweetalert": "^2.1.2",
-        "tinymce": "^5.8.2"
+        "tinymce": "^5.9.1"
     }
 }