build: fix coverage generation

Changes in command line options for nyc resulted in the
coverage target no longer working.

Pin the major version of nyc and update the options to
get it working again.

PR-URL: https://github.com/nodejs/node/pull/23769
Fixes: https://github.com/nodejs/node/issues/23690


Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Refael Ackermann <refack@gmail.com>
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>
Reviewed-By: George Adams <george.adams@uk.ibm.com>