docs: add links for creating R2 access API tokens in README

Author: krzysztof-palka-monogo

.changeset/rclone-batch-upload.md

@@ -40,3 +40,7 @@ export R2_SECRET_ACCESS_KEY=your_secret
 export R2_ACCOUNT_ID=your_account
 opennextjs-cloudflare deploy  # batch upload automatically used
 ```
+
+**Note:**
+
+You can follow documentation https://developers.cloudflare.com/r2/api/tokens/ for creating API tokens with appropriate permissions for R2 access.

packages/cloudflare/README.md

@@ -66,6 +66,10 @@ export R2_SECRET_ACCESS_KEY=your_secret_access_key
 export R2_ACCOUNT_ID=your_account_id
 ```
 
+**Note:**
+
+You can follow documentation https://developers.cloudflare.com/r2/api/tokens/ for creating API tokens with appropriate permissions for R2 access.
+
 **Benefits:**
 
 - Significantly faster uploads for large caches using parallel transfers