debhelper to your Build-Depends line in F<debian/control>. You should
build-depend on a version of debhelper equal to (or greater than) the
debhelper compatibility level your package uses. So if your package used
-compatibility level 7:
+compatibility level 9:
- Build-Depends: debhelper (>= 7)
+ Build-Depends: debhelper (>= 9)
=head1 ENVIRONMENT