fix: update docs on supported config file extensions (#917)

* allow .cjs files for ESModule based packages

* trailing comma

* adds all supported file extensions to README

* a bit clearer on supported files

Author: ksmithut

README.md

@@ -97,8 +97,11 @@ Options:
 Starting with v3.1 you can now use different ways of configuring it:
 
 - `lint-staged` object in your `package.json`
-- `.lintstagedrc` file in JSON or YML format
-- `lint-staged.config.js` file in JS format
+- `.lintstagedrc` file in JSON or YML format, or you can be explicit with the file extension:
+  - `.lintstagedrc.json`
+  - `.lintstagedrc.yaml`
+  - `.lintstagedrc.yml`
+- `lint-staged.config.js`, `.lintstagedrc.js`, or `.lintstagedrc.cjs` file in JS format
 - Pass a configuration file using the `--config` or `-c` flag
 
 See [cosmiconfig](https://github.com/davidtheclark/cosmiconfig) for more details on what formats are supported.