build: update built-in Talk version

Signed-off-by: GitHub <noreply@github.com>

Author: nextcloud-command

package.json

@@ -41,8 +41,8 @@
     "typecheck": "vue-tsc --noEmit"
   },
   "talk": {
-    "stable": "v21.0.4",
-    "beta": "v21.1.0-rc.2",
+    "stable": "v20.1.7",
+    "beta": "v21.1.0-rc.4",
     "dev": "main"
   },
   "dependencies": {