Update _index.md

The credentials for the secret need to either go into `stringData` or be base64-encoded.

content/rancher/v2.5/en/backups/migrating-rancher/_index.md

@@ -36,7 +36,7 @@ kind: Secret
 metadata:
   name: s3-creds
 type: Opaque
-data:
+stringData:
   accessKey: <Enter your access key>
   secretKey: <Enter your secret key>
 ```
@@ -94,4 +94,4 @@ Use the same version of Helm to install Rancher, that was used on the first clus
 helm install rancher rancher-latest/rancher \
   --namespace cattle-system \
   --set hostname=<same hostname as the server URL from the first Rancher server> \
-```
+```