Feature: Simplify usage by supporting new default loop and new Socket API. (#114 and #115 by @SimonFrings)

// old (still supported)
$factory = new Clue\React\Redis\Factory($loop);

// new (using default loop)
$factory = new Clue\React\Redis\Factory();

Feature: Improve error reporting, include Redis URI and socket error codes in all connection errors. (#116 by @clue)

Documentation improvements and updated examples. (#117 by @clue, #112 by @Nyholm and #113 by @PaulRotmann)

Improve test suite and use GitHub actions for continuous integration (CI). (#111 by @SimonFrings)