Ruler v0.4 improves support for modern PHP. It is API compatible with…

… v0.3.x, and should be a drop-in replacement other than...

- Drops support for PHP < 7.4. Thanks @DemigodCode!
- Updated, more complete, types.
- Deprecated Contains Operator has been removed (in favor of StringContains and SetContains Operators).

 - Switch from Travis to GitHub Actions. Thanks @davidmpaz!

 - Fix warnings in PHP7.2+. Thanks @mjrider!
 - Better test and composer.json config. Thanks @peter279k and @flavius!
 - Support StringContainsInsensitive in rulebuilder API. Thanks @ttrajanov-modus!
 - Better Set operations for objects! Thanks @ludicruz!

 * Add Set and Arithmetic Operators. Thanks @ludicruz!

 * Allow registering custom Operators. Thanks @tophsic!
 * Add StartsWith and EndsWith Operators. Thanks @gogume!
 * Add case-insensitive string comparison Operators.
 * Remove dependency on Pimple.
 * Deprecate Contains Operator in favor of discrete StringContains and SetContains Operators.

Add `Contains` and `DoesNotContain` operators for strings and arrays.

Thanks @malaney!

Ruler v0.1.0