Merge pull request #957 from anandfresh/contributing

Contribution note Update for Issue #952

Author: k8s-ci-robot

CONTRIBUTING.md

@@ -12,6 +12,8 @@ We'd love to accept your patches! Before we can accept them you need to sign Clo
 ## Reporting an issue
 If you have any problem with the package or any suggestions, please file an [issue](https://github.com/kubernetes-client/javascript/issues).
 
+Note: Before raising a new issue, please do check the existing issues and make sure it is not a duplicate one.
+
 ## Contributing a Patch
 1. Submit an issue describing your proposed change to the repo.
 2. Fork this repo, develop and test your code changes.