My name is Bobby and I am a member of the Webtasks team. It looks like there was some confusion surrounding your question and you were given some misleading information.
Webtask.io and Hooks both support the All NPM feature. Rules do not. The Github deployment extension is used to deploy Rules and does not offer the ability to declare dependencies on NPM modules.
To make sure I get you the correct information, can you tell me a bit more about your use case? Are you currently using webtask.io at all? Or are you simply attempting to consume tslib in your Rules which are deployed using the github deployment extension?
Once again, sorry for the confusion. I will make sure we get this tracked down for you.