Updated Security Configuration (markdown)

Security-Configuration.md

@@ -82,6 +82,9 @@ Here is my `security.toml` file content:
 [jwt.signing]
 key = "blahblahblahblah"
 
+[jwt.filer_signing]
+key = "blahblahblahblah"
+
 # all grpc tls authentications are mutual 
 [grpc]
 ca = "/Users/chris/.seaweedfs/out/SeaweedFS_CA.crt"