doc: add pre-commit url

Author: satra

CONTRIBUTING.md

@@ -102,7 +102,7 @@ When opening a pull request, please use one of the following prefixes:
 
 **5. Install pre-commit.**
 
-[pre-commit]() is a git hook for running operations at commit time. To use it in
+[pre-commit](https://pre-commit.com/) is a git hook for running operations at commit time. To use it in
 your environment, do `pip install pre-commit` following by `pre-cmmit install`
 inside your source directory.