v2.5.0 Get rid of setting ini_set globally, minor enhancements

1. Fixing: Using ini_set('mbstring.substitute_character', "none"); in a library can be risky because it affects global PHP runtime settings, which may unintentionally impact other code that relies on the default value of mbstring.substitute_character.
   (#71)

2. Minor enhancements (#72):

• Support Windows-style line separators in RobotsTxtParser. Resolve #68
• Fixing typo with boolean value in RobotsTxtValidator which can speed-up isUrlAllow function in some cases.

3. Add Github Actions (#69):

• run PHPUnit tests on PHP 7.4, 8.0, 8.1, 8.2, 8.3, 8.4.
• apply psalm
• apply php-cs-fixer