[doc] Fix minor README.md grammar issue
diff --git a/README.md b/README.md
index ac919ca..73de945 100644
--- a/README.md
+++ b/README.md
@@ -32,8 +32,8 @@
 
 ## How to contribute
 
-Have a look at [CONTRIBUTING](./CONTRIBUTING.md) for guidelines how
-to contribute code to this repository.
+Have a look at [CONTRIBUTING](./CONTRIBUTING.md) for guidelines on how to
+contribute code to this repository.
 
 ## Licensing