No swift_version in podspec

[Fyb3roptik]

Getting this error on the new cocoapods:

- `AuthorizeNetAccept` does not specify a Swift version and none of the targets (`Unity-iPhone`) integrating it have the `SWIFT_VERSION` attribute set. Please contact the author or set the `SWIFT_VERSION` attribute in at least one of the targets that integrate this pod.

It can be resolved by adding:

s.swift_version = '4.0'

to the podspec. Please fix ASAP!