feat(v2.1): release 2.1 for PHPUnit 12.5.0...

Author: rtm-ctrlz

README.md

@@ -15,7 +15,7 @@ This library follows [SemVer](https://semver.org/).
 But major versions are used to indicate compatibility with PHPUnit versions:
 - `1.x` is compatible with PHPUnit 9.6...12.0.8
 - `2.x` is compatible with PHPUnit 12.0.9...12.4.x
-- `3.x` is compatible with PHPUnit 12.5.0...
+- `2.1` is compatible with PHPUnit 12.5.0...
 
 ## Usage
 To use with PHPUnit: