Create a carbon() helper

[ArthurYdalgo]

Not sure if it'd be relevant, and I know that the now() method already returns a new instance of Carbon, but I think a carbon() helper method could be nice.

// src/Illuminate/Foundation/helpers.php

if (! function_exists('carbon')) {
    /**
     * Create a new Carbon instance.
     *
     * @param DateTimeInterface|string|null $time
     * @param DateTimeZone|string|null      $tz
     * @return \Illuminate\Support\Carbon
     * 
     * @throws InvalidFormatException
     */
    function carbon($time = null, $tz = null)
    {
        return Date::parse($time, $tz);
    }
}

[ArthurYdalgo]

Here is the PR