Linting your podspec after introducing Swift

I have written a few CocoaPods and I'm in the process of converting these Objective-C projects over to Swift. During which I've encountered a few issues such as switching from a Static Library project to a Framework project however the issue that took the most time to overcome was a set of errors when I run pod spec lint on my ConvenientFileManager pod I got the following output:

-> ConvenientFileManager (2.0.0)
    - ERROR | [iOS] public_header_files: The pattern matches non-header files (ConvenientFileManager/Cache/NSFileManager+CFMCache.swift, ConvenientFileManager/Documents/NSFileManager+CFMDocuments.swift, ConvenientFileManager/Persistence/NSFileManager+CFMPersistence.swift).
    - ERROR | [iOS] xcodebuild: Returned an unsuccessful exit code. You can use `--verbose` for more information.
    - NOTE  | xcodebuild:  :1:9: note: in file included from :1:
    - ERROR | xcodebuild:  Target Support Files/ConvenientFileManager/ConvenientFileManager-umbrella.h:3:9: error: 'NSFileManager+CFMCache.swift' file not found
    - NOTE  | xcodebuild:  :0: error: could not build Objective-C module 'ConvenientFileManager'

So I went back and re-ran using --verbose and got some more information on the error:

<module-includes>:1:9: note: in file included from <module-includes>:1:
#import "Headers/ConvenientFileManager-umbrella.h"
        ^
/var/folders/2v/51_f5pnn7y5dq0yz453yb4q40000gq/T/CocoaPods/Lint/Pods/Target Support Files/ConvenientFileManager/ConvenientFileManager-umbrella.h:3:9: error: 'NSFileManager+CFMCache.swift' file not found
#import "NSFileManager+CFMCache.swift"
        ^
<unknown>:0: error: could not build Objective-C module 'ConvenientFileManager'

From this I Googled around and tried some of the suggestions to solve this issue but without any luck. It wasn't until I stumbled upon this issue on Github: https://github.com/Danappelxx/SwiftMongoDB/issues/2

That it clicked that this error could be related to what I had in my podspec rather than in my project. When I started the conversion over to Swift I quickly updated my podspec to remove references to {h,m} to swift however what I hadn't done was to remove s.public_header_files from my podspec file altogether. Once I done so the errors that I was having during pod lint went away.

For reference is my current podspec file:

Pod::Spec.new do |s|

  s.name         = "ConvenientFileManager"
  s.version      = "2.0.0"
  s.summary      = "A suite of categories to ease using NSFileManager for common tasks."

  s.homepage     = "http://www.williamboles.me"
  s.license      = { :type => 'MIT', 
                       :file => 'LICENSE.md' }
  s.author       = "William Boles"

  s.platform     = :ios, "9.0"

  s.source       = { :git => "https://github.com/wibosco/ConvenientFileManager.git", 
                       :branch => "master", 
                       :tag => s.version }

  s.source_files  = "ConvenientFileManager/**/*.swift"

  s.requires_arc = true

end