Updated Storage backend examples (markdown)

Storage-backend-examples.md

@@ -4,7 +4,7 @@ S3Proxy supports [IAM roles for service accounts](https://docs.aws.amazon.com/ek
 
 ```
 s3proxy.endpoint=http://0.0.0.0:8080
-s3proxy.authorization=aws-s3
+s3proxy.authorization=aws-v2-or-v4
 s3proxy.identity=local-identity
 s3proxy.credential=local-credential
 jclouds.provider=aws-s3