chore: update version requirement for zotero 8

Author: windingwind

addon/manifest.json

@@ -13,8 +13,8 @@
     "zotero": {
       "id": "__addonID__",
       "update_url": "__updateURL__",
-      "strict_min_version": "7.0.0-beta.70",
-      "strict_max_version": "8.0.*"
+      "strict_min_version": "7.9.9",
+      "strict_max_version": "8.1.*"
     }
   }
 }