npm-registry-client@4.0.3

Send GitHub the JSON accepts header it's looking for when we request a
tarball via an HTML redirect page. The internet is terrible.

Fixes #6729.
Put npm-debug.log file in the cache folder, not cwd

This should prevent mishaps like #1548, while avoiding overly
configurable options that make it hard to predict where the file
will show up.

Fix #1584
Close #5252
update test for new behavior