docs: update

Author: r1tsuu

README.md

@@ -43,7 +43,7 @@ volumes:
 BLOB_READ_WRITE_TOKEN=vercel_blob_rw_emulator_local  # any vercel_blob_rw_<id>_<anything> value works
 VERCEL_BLOB_API_URL=http://localhost:3100/api/blob
 NEXT_PUBLIC_VERCEL_BLOB_API_URL=http://localhost:3100/api/blob
-STORAGE_VERCEL_BLOB_BASE_URL=http://localhost:3100    # Payload-specific
+STORAGE_VERCEL_BLOB_BASE_URL=http://localhost:3100    # Must be set if you use @payloadcms/vercel-blob
 VERCEL_BLOB_RETRIES=0                                 # recommended for tests
 VERCEL_BLOB_CALLBACK_URL=http://localhost:3000        # your app's base URL; omit if onUploadCompleted is unused
 ```