Log Message:
npm: updated to 6.10.2

v6.10.2:

tl;dr - Fixes several issues with the cache when npm is run as sudo on Unix systems.

TESTING
check test cache for root-owned files
run sudo tests on Travis-CI
set --no-esm tap flag
add script to run tests and leave fixtures for inspection and debugging

BUGFIXES
add a util for writing arbitrary files to cache This prevents metrics timing and \ 
debug logs from becoming root-owned.
infer cache owner from parent dir in correct-mkdir util
ensure correct owner on cached all-packages metadata
report server error on failure
Fix npm ci with file: dependencies.