Bump tinymce from 5.10.7 to 5.10.8 in /samples/react-tinymce

Bumps [tinymce](https://github.com/tinymce/tinymce/tree/HEAD/modules/tinymce) from 5.10.7 to 5.10.8.
- [Changelog](https://github.com/tinymce/tinymce/blob/5.10.8/modules/tinymce/CHANGELOG.md)
- [Commits](https://github.com/tinymce/tinymce/commits/5.10.8/modules/tinymce)

---
updated-dependencies:
- dependency-name: tinymce
  dependency-type: direct:production
...

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

samples/react-tinymce/package-lock.json

@@ -24575,9 +24575,9 @@
       }
     },
     "tinymce": {
-      "version": "5.10.7",
+      "version": "5.10.8",
-      "resolved": "https://registry.npmjs.org/tinymce/-/tinymce-5.10.7.tgz",
+      "resolved": "https://registry.npmjs.org/tinymce/-/tinymce-5.10.8.tgz",
-      "integrity": "sha512-9UUjaO0R7FxcFo0oxnd1lMs7H+D0Eh+dDVo5hKbVe1a+VB0nit97vOqlinj+YwgoBDt6/DSCUoWqAYlLI8BLYA=="
+      "integrity": "sha512-iyoo3VGMAJhLMDdblAefKvYgBRk9kQi58GTwAmoieqsyggGsKZWlQl/YY6nTILFHUCA1FhYu0HdmM5YYjs17UQ=="
     },
     "tmp": {
       "version": "0.0.33",

samples/react-tinymce/package.json

@@ -22,7 +22,7 @@
     "react": "15.6.2",
     "react-dom": "15.6.2",
     "react-html-parser": "^2.0.2",
-    "tinymce": "^5.10.7"
+    "tinymce": "^5.10.8"
   },
   "devDependencies": {
     "@microsoft/sp-build-web": "~1.16.1",