Fix typo in contributing.md (sindresorhus#1423)

yeskunall · sindresorhus · commit c1d669778dfb · 2018-10-17T12:06:55.000+07:00
diff --git a/contributing.md b/contributing.md
@@ -2,7 +2,7 @@
 
 Please note that this project is released with a [Contributor Code of Conduct](code-of-conduct.md). By participating in this project you agree to abide by its terms.
 
-## Adding a awesome list
+## Adding an awesome list
 
 Please ensure your pull request adheres to the [list guidelines](pull_request_template.md).
 
