Fix serbanghita#771 Update README.md (serbanghita#772)

Fix link to How to Contribute

Author: coderintherye

README.md

@@ -74,7 +74,7 @@ or include the dependency in the `composer.json` file:
 #### Contribute
 
 *Submit a PR*
-> Submit a pull request but before make sure you read [how to contribute](../../docs/CONTRIBUTING.md) guide.
+> Submit a pull request but before make sure you read [how to contribute](docs/CONTRIBUTING.md) guide.
 
 *Donate*