Update getSupportedBiometryType instructions (#292)
Update getSupportedBiometryType instructions (#292)

Removes a notice under `getSupportedBiometryType` that is no longer valid after a recent API change (https://github.com/oblador/react-native-keychain/pull/240) . This method always returns the biometry type, if the device supports it. It only returns `null` if the device doesn't support any of the biometry types.
oblador/react-native-keychain,oblador/react-native-keychain,oblador/react-native-keychain,oblador/react-native-keychain,oblador/react-native-keychain,oblador/react-native-keychain