Fixed link in PR template to CONTRIBUTING

.github/PULL_REQUEST_TEMPLATE.md

@@ -7,7 +7,7 @@ attention.
 -->
 
 - Have you signed the [contributor license agreement](https://www.elastic.co/contributor-agreement)?
-- Have you followed the [contributor guidelines](https://github.com/elastic/elasticsearch/blob/master/.github/CONTRIBUTING.md)?
+- Have you followed the [contributor guidelines](https://github.com/elastic/elasticsearch/blob/master/CONTRIBUTING.md)?
 - If submitting code, have you built your formula locally prior to submission with `gradle check`?
 - If submitting code, is your pull request against master? Unless there is a good reason otherwise, we prefer pull requests against master and will backport as needed.
 - If submitting code, have you checked that your submission is for an [OS that we support](https://www.elastic.co/support/matrix#show_os)?