Move to debhelper compat level 10

- stop using dh --parallel, it's the default now
  - don't use autoreconf and systemd addons explicitly, they are
    the default now

debian/rules

@@ -4,7 +4,7 @@ export DEB_BUILD_MAINT_OPTIONS = hardening=+all
 export DEB_LDFLAGS_MAINT_APPEND = -Wl,--as-needed
 
 %:
-	dh $@ --parallel --with=autoreconf,gir,systemd
+	dh $@ --with=gir
 
 override_dh_auto_clean:
 	if [ -e Makefile ]; then dh_auto_clean; fi