v2.2.0

In this release

• Several code improvements by @localheinz
• The integer rule has now the option to do a strict integer check thanks to @rcatlin
• a ->string() validation rule is now available to check if a value is a string thanks to @localheinz
• a ->float() validation rule is now available to check if a value is a float thanks to @localheinz
• The dependencies of the project are now removed, and are suggested via composer instead. If you want to use the ->phone() or ->creditCard() rules, the corresponding libraries must be installed manually.