add node/npm version to ISSUE_TEMPLATE.md

Summary:
A huge number of Issues are opened with some key information about node/npm versions missing. Adding this information as a required part of the ISSUE_TEMPLATE may help issues get closed faster.

Once merged in, check ISSUE_TEMPLATE by opening new issue, verify new line is there.
Closes https://github.com/facebook/react-native/pull/14422

Differential Revision: D5865411

Pulled By: hramos

fbshipit-source-id: 70e776c8635de38fb149471656e6d260f9eb2537