[5.6] Updated to use new release of cron-expression

[dragonmantank]

This updates the Laravel Framework to support the new 2.x branch of cron-expression.

I looked through the test set to fix what I could find that relies on the library, and the only test I could not fix was Illuminate\Tests\Console\Scheduling\EventTest::testBuildCommand ... I'm just not exactly sure how all that is managed, so the hash it generates is different than what the test expects. If I missed any other tests, let me know and I'll gladly update this PR. Most of the test changes are because cron-expression has dropped support for the Year place.

This is in response to mtdowling/cron-expression#153 and #19532. More detail on the package name change can be found at http://ctankersley.com/2017/10/12/cron-expression-update/

[Dylan-DPC-zz]

The Illuminate\Tests\Console\Scheduling\EventTest::testBuildCommand test is failing

[dragonmantank]

Right, I mention that above. I don't know exactly what that test is doing in the first place (I don't use Laravel) so I'm not sure what the proper fix is. While I could just change the hash, I don't know that it's supposed to change. Any help would be appreciated with that test.

[taylorotwell]

Thanks I'll take a look

[dragonmantank]

Thanks @taylorotwell !

[themsaid]

Fixed the test by applying the new mutex after the expression has changed.

[taylorotwell]

Thanks