Update CONTRIBUTING.md

Fixes typo in contributing doc

CONTRIBUTING.md

@@ -25,8 +25,7 @@ This repository uses [conventional commits](https://www.conventionalcommits.org/
 ## Pull Requests
 As mentioned above, all pull requests should target `dev`.
 
-Before opening your pull request, please ensure that the following
-following requirements are met:
+Before opening your pull request, please ensure that the following requirements are met:
 * You have run `flutter pub get` at the package level
 * You have incremented the version number in `pubspec.yaml` properly
 * You have updated the `CHANGELOG.md` file accordingly
@@ -38,4 +37,4 @@ A note for authorized maintainers: Pull requests should **always** be merged via
 
 ### Versioning
 
-`macos_ui` uses semantic versioning. Please ensure your updates follow this method accordingly.  
+`macos_ui` uses semantic versioning. Please ensure your updates follow this method accordingly.