chore(version): Update package versions to 3.13.0-beta.21 [skip ci]

platform/ui/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@ohif/ui",
-  "version": "3.13.0-beta.20",
+  "version": "3.13.0-beta.21",
   "description": "A set of React components for Medical Imaging Viewers",
   "author": "OHIF Contributors",
   "license": "MIT",