UpdateHelper\ComposerPlugin contains 2 abstract methods and must ther efore be declared abstract or implement the remaining methods code example

Example: PHP Fatal error: Class UpdateHelper\ComposerPlugin contains 2 abstract methods and must therefore be declared abstract or implement the remaining methods (Composer\Plugin\PluginInterface::deactivate

composer update kylekatarnls/update-helper
#if doesnot work use following:
composer update --prefer-source