updated Contribution Guidelines link

original .github/CONTRIBUTING.html link produces 404 error. changed link to https://github.com/magento/magento2-functional-testing-framework/blob/develop/.github/CONTRIBUTING.md

Author: hickskenh

README.md

@@ -70,11 +70,11 @@ See the license [here][] or contact [license@magentocommerce.com][] for a copy.
 
 <!-- Link Definitions -->
 [Getting Started]: docs/getting-started.md
-[Contribution Guidelines]: .github/CONTRIBUTING.html
+[Contribution Guidelines]: https://github.com/magento/magento2-functional-testing-framework/blob/develop/.github/CONTRIBUTING.md
 [DevDocs Contributing]: https://github.com/magento/devdocs/blob/master/.github/CONTRIBUTING.md
 [security@magento.com]: mailto:security@magento.com
 [encryption key]: https://info2.magento.com/rs/magentoenterprise/images/security_at_magento.asc
 [here]: https://magento.com/security/reporting-magento-security-issue
 [Security Alert Notifications]: https://magento.com/security/sign-up
 [here]: LICENSE_AGPL3.txt
-[license@magentocommerce.com]: mailto:license@magentocommerce.com
+[license@magentocommerce.com]: mailto:license@magentocommerce.com