Podspec swift version must be updated.

[farshadmb]

Hi Dears,
The framework's swift version has been updated to 5.0. however, the swift version in pospec needs to be updated to the latest swift version.

MagazineLayout/MagazineLayout.podspec

Line 9 in d2eb5c5

s.swift_version = '4.0'

the pod install might face the error where Podfile has specified swift version support.
supports_swift_versions '>= 5.0'

[!] Unable to determine Swift version for the following pods:

- `MagazineLayout` does not specify a Swift version (`4.0`) that is satisfied by any of targets integrating it.

please update the swift version in pod spec file.