Add capture argument matcher

[jasonmccreary]

This adds a simple closure argument matcher which will capture the argument into a local variable. This provides an easy way to store an argument passed to a mocked method for more complex validation without having to wrap all the logic inline within a Mockery::on() closure.

Example:

$temp = null;
$mock->expects('foo')
    ->with(Mockery::capture($temp));

$mock->foo($someObject);

// $temp === $someObject

[jasonmccreary]

If approved, glad to add a section to the documentation. 👍

[davedevelopment]

Love it 👍

[robertbasic]

Nice, thanks! 👍

[mfn]

OMG, this looks so cool!

[jasonmccreary]

@robertbasic great! Shall I open an accompanying PR for the docs?

[robertbasic]

@jasonmccreary maybe add it to this one? Either works fine, thanks :)

[jasonmccreary]

@robertbasic oh, der, it's a monorepo. Will do. 👍

[jasonmccreary]

@robertbasic took a stab at writing some documentation. Let me know.

[robertbasic]

@jasonmccreary looks good, thanks!

[jasonmccreary]

@robertbasic Yay! Any chance for tagging a release. Would love to tweet/demo this new matcher afterward. 👍

[robertbasic]

@jasonmccreary I need to catch up on the changelog and then to tag a release. Early next week as it stands now, that ok?

[jasonmccreary]

@roberbase, Of course. I'll keep an eye out and do another tweet once it's tagged.