deps: upgrade npm to 7.6.0
PR-URL: https://github.com/nodejs/node/pull/37559
Fixes: https://github.com/hidden
Reviewed-By: Luigi Pinca <[email protected]>
Reviewed-By: Rich Trott <[email protected]>
Reviewed-By: Michaël Zasso <[email protected]>