Exclude watchOS extensions from pod

Kingfisher.podspec

@@ -37,7 +37,7 @@ Pod::Spec.new do |s|
   s.source_files  = ["Sources/*.swift", "Sources/Kingfisher.h", "Sources/Kingfisher.swift"]
   s.public_header_files = ["Sources/Kingfisher.h"]
   
-  s.osx.exclude_files = ["Sources/AnimatedImageView.swift", "Sources/UIButton+Kingfisher.swift"]
+  s.osx.exclude_files = ["Sources/AnimatedImageView.swift", "Sources/UIButton+Kingfisher.swift", "Sources/WKInterfaceImage+Kingfisher.swift"]
   s.watchos.exclude_files = ["Sources/AnimatedImageView.swift", 
                              "Sources/UIButton+Kingfisher.swift", 
                              "Sources/ImageView+Kingfisher.swift", 
@@ -46,8 +46,8 @@ Pod::Spec.new do |s|
                              "Sources/Filter.swift",
                              "Sources/Placeholder.swift"
                             ]
-  s.ios.exclude_files = "Sources/NSButton+Kingfisher.swift"
-  s.tvos.exclude_files = "Sources/NSButton+Kingfisher.swift"
+  s.ios.exclude_files = ["Sources/NSButton+Kingfisher.swift", "Sources/WKInterfaceImage+Kingfisher.swift"]
+  s.tvos.exclude_files = ["Sources/NSButton+Kingfisher.swift", "Sources/WKInterfaceImage+Kingfisher.swift"]
 
   s.requires_arc = true
   s.framework = "CFNetwork"