Update README with information about linting / formatting (#254)

* Fix CI status badge in README

* Update README with information about linting and formatting

Author: mattt

README.md

@@ -8,8 +8,7 @@
   <br/>
 </p>
 
-
-[![Unit Tests](https://github.com/huggingface/swift-transformers/actions/workflows/unit-tests.yml/badge.svg)](https://github.com/huggingface/swift-transformers/actions/workflows/unit-tests.yml)
+[![Unit Tests](https://github.com/huggingface/swift-transformers/actions/workflows/ci.yml/badge.svg)](https://github.com/huggingface/swift-transformers/actions/workflows/unit-tests.yml)
 [![](https://img.shields.io/endpoint?url=https%3A%2F%2Fswiftpackageindex.com%2Fapi%2Fpackages%2Fhuggingface%2Fswift-transformers%2Fbadge%3Ftype%3Dswift-versions)](https://swiftpackageindex.com/huggingface/swift-transformers)
 [![](https://img.shields.io/endpoint?url=https%3A%2F%2Fswiftpackageindex.com%2Fapi%2Fpackages%2Fhuggingface%2Fswift-transformers%2Fbadge%3Ftype%3Dplatforms)](https://swiftpackageindex.com/huggingface/swift-transformers)
 
@@ -112,8 +111,12 @@ Swift Transformers is a community project and we welcome contributions. Please
 check out [Issues](https://github.com/huggingface/swift-transformers/issues)
 tagged with `good first issue` if you are looking for a place to start!
 
-Please ensure your code passes the build and test suite before submitting a pull
-request. You can run the tests with `swift test`.
+Before submitting a pull request, please ensure your code:
+
+- Passes the test suite (`swift test`)
+- Passes linting checks (`swift format lint --recursive .`)
+
+To format your code, run `swift format -i --recursive .`.
 
 ## License