Input argument type has changed from string to array for setAllowedMethods()

At the first time was introduced the patch which was adding the method and allowed developers to set allowed payment methods via string, separating each other via comma.

Example:

$payment->setAllowedMethods('a,b,c');

After it has been merged an another approach has been discussed and been applied afterwards.

So, those, who has used the 7.x-2.x-dev release of a module and setAllowedMethods() method especially, should take care about implementation and change previous usage by:

$payment->setAllowedMethods(['a', 'b', 'c']);