feat: run the hook only if CircleCI config file is changed (#3)

Author: YaraslauZhylko

.pre-commit-hooks.yaml

@@ -2,4 +2,6 @@
   name: Validate CircleCI config
   description: This hook validate CircleCI config 
   entry: circleci_validate.sh
-  language: script
+  language: script
+  files: .circleci/config.yml
+  pass_filenames: false

README.md

@@ -7,7 +7,7 @@
 ```bash
 $ cat .pre-commit-config.yaml
 - repo: https://github.com/zahorniak/pre-commit-circleci.git
-  rev: v0.2 # Ensure this is the latest tag, comparing to the Releases tab
+  rev: v0.3 # Ensure this is the latest tag, comparing to the Releases tab
   hooks:
     - id: circleci_validate
 ```