react-native-nordic-dfu: Error on pod install

Steps to reproduce:

react-native init AwesomeProject
cd AwesomeProject
npm install --save react-native-nordic-dfu
cd ios
touch Podfile

My Podfile:

target 'AwesomeProject' do
 rn_path = '../node_modules/react-native'

 # See http://facebook.github.io/react-native/docs/integration-with-existing-apps.html#configuring-cocoapods-dependencies
 pod 'yoga', path: "#{rn_path}/ReactCommon/yoga/yoga.podspec"
 pod 'React', path: rn_path, subspecs: [
   'Core',
   'CxxBridge',
   'DevSupport',
   'RCTActionSheet',
   'RCTAnimation',
   'RCTGeolocation',
   'RCTImage',
   'RCTLinkingIOS',
   'RCTNetwork',
   'RCTSettings',
   'RCTText',
   'RCTVibration',
   'RCTWebSocket',
 ]


 # React Native third party dependencies podspecs
 pod 'DoubleConversion', :podspec => "#{rn_path}/third-party-podspecs/DoubleConversion.podspec"
 pod 'glog', :podspec => "#{rn_path}/third-party-podspecs/glog.podspec"
 # If you are using React Native <0.54, you will get the following error:
 # "The name of the given podspec `GLog` doesn't match the expected one `glog`"
 # Use the following line instead:
 #pod 'GLog', :podspec => "#{rn_path}/third-party-podspecs/GLog.podspec"
 pod 'Folly', :podspec => "#{rn_path}/third-party-podspecs/Folly.podspec"

 pod 'react-native-nordic-dfu', :path => '../node_modules/react-native-nordic-dfu'

end

post_install do |installer|
 installer.pods_project.targets.each do |target|
   if target.name == "React"
     target.remove_from_project
   end
 end
end

Install pods:

pod install

I get an error:

[!] Unable to determine Swift version for the following pods:
 - `iOSDFULibrary` does not specify a Swift version and none of the targets (`AwesomeProject`) 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.