Bug#867298: npm2deb: please bump debhelper and Standards-Version

[Johannes Schauer]

Package: npm2deb
Version: 0.2.7-1
Severity: wishlist

Standards-Version 3.9.8 is outdated. npm2deb should generate version
4.0.0 instead.

The current recommended compat level for debhelper is 10. npm2deb should
use that one instead of compat level 9.