Fix log level

Author: ketan

src/main/java/cd/go/authorization/github/executors/ValidateUserRequestExecutor.java

@@ -47,7 +47,7 @@ public GoPluginApiResponse execute() throws Exception {
             LOG.error(format("[Is Valid User] User %s does not exist in GitHub.", request.getUsername()));
             return DefaultGoPluginApiResponse.error(String.format("User '%s' does not exist in GitHub.", request.getUsername()));
         } else {
-            LOG.info(format("[Is Valid User] %s is valid user.", request.getUsername()));
+            LOG.debug(format("[Is Valid User] %s is valid user.", request.getUsername()));
             return DefaultGoPluginApiResponse.success("");
         }
     }