PHP7.4 array access violation

[Nacoma]

PHP7.4 now triggers a notice (which is commonly converted into an ErrorException) when accessing non-arrayable types (int, float, etc).

This causes an exception when trying to fetch shipping rates on line 35: https://github.com/goshippo/shippo-php-client/blob/e4b577a0f45675db5df54e14877a2a9f463dfcad/lib/Shippo/Util.php#L30-L35

[bobbarn]

Nacoma did you ever find a work around for this? Edit saw your pull request - thanks

if (is_string($k) && $k[0] == '_') {
                continue;
            }