Issue #89: Replace Psalm with PHPStan

Signed-off-by: horea <[email protected]>

Author: Howriq

docs/book/v5/overview.md

@@ -15,7 +15,7 @@ Dotkernel's mail service.
 [![GitHub license](https://img.shields.io/github/license/dotkernel/dot-mail)](https://github.com/dotkernel/dot-mail/blob/5.2/LICENSE.md)
 
 [![Build Static](https://github.com/dotkernel/dot-mail/actions/workflows/continuous-integration.yml/badge.svg?branch=5.2)](https://github.com/dotkernel/dot-mail/actions/workflows/continuous-integration.yml)
-[![codecov](https://codecov.io/gh/dotkernel/dot-mail/graph/badge.svg?token=G51NEHYKD3)](https://codecov.io/gh/dotkernel/dot-mail)
+[![codecov](https://codecov.io/gh/dotkernel/dot-mail/branch/5.2/graph/badge.svg?token=G51NEHYKD3)](https://codecov.io/gh/dotkernel/dot-mail)
 [![PHPStan](https://github.com/dotkernel/dot-mail/actions/workflows/static-analysis.yml/badge.svg?branch=5.2)](https://github.com/dotkernel/dot-mail/actions/workflows/static-analysis.yml)
 
 ## Extra features