GH Actions: fix CI not running on main

Also fix the "Unreleased" link in the changelog.

Author: jrfnl

.github/workflows/ci.yml

@@ -4,7 +4,7 @@ on:
   # Run on all pushes and pull requests.
   push:
     branches:
-      - master
+      - main
   pull_request:
   # Also run this workflow on day 10 of every month as the repo isn't that active.
   schedule:

CHANGELOG.md

@@ -64,7 +64,7 @@ Initial release.
 [PHP_CodeSniffer]: https://github.com/squizlabs/php_codesniffer/
 [PHPCompatibility]: https://github.com/PHPCompatibility/PHPCompatibility
 
-[Unreleased]: https://github.com/PHPCSStandards/PHPCSDevCS/compare/master...HEAD
+[Unreleased]: https://github.com/PHPCSStandards/PHPCSDevCS/compare/main...HEAD
 [1.1.5]: https://github.com/PHPCSStandards/PHPCSDevCS/compare/1.1.4...1.1.5
 [1.1.4]: https://github.com/PHPCSStandards/PHPCSDevCS/compare/1.1.3...1.1.4
 [1.1.3]: https://github.com/PHPCSStandards/PHPCSDevCS/compare/1.1.2...1.1.3