🍫 Podspec: Unrecognized `swift_version` key.

[phatblat]

The error below does not appear when running pod lib lint but it does appear while attempting to push a new spec version to trunk.

$ pod trunk push Commandant.podspec
...
[!] The Pod Specification did not pass validation.
The following validation failed:
- Warnings: Unrecognized `swift_version` key.

This is using CocoaPods 1.6.1.

[phatblat]

Worked around this for now by allowing warnings during publishing.

$ pod trunk push Commandant.podspec --allow-warnings
...
--------------------------------------------------------------------------------
 🎉  Congrats

 🚀  Commandant (0.16.0) successfully published
 📅  April 10th, 21:01
 🌎  https://cocoapods.org/pods/Commandant
 👍  Tell your friends!
--------------------------------------------------------------------------------

CocoaPods 1.7.0 changes this key to swift_versions for multiple version support. Perhaps updating the gem (after beta) will resolve this warning.