Bump debhelper from old 10 to 12.

+ Use dh_installsystemd rather than deprecated dh_systemd_enable.
+ Use dh_installsystemd rather than deprecated dh_systemd_start.

Changes-By: lintian-brush
Fixes: lintian: package-uses-old-debhelper-compat-version
See-also: https://lintian.debian.org/tags/package-uses-old-debhelper-compat-version.html

debian/compat

-10
+12

debian/control

@@ -2,7 +2,7 @@ Source: acmeserver
 Section: admin
 Priority: optional
 Maintainer: Autistici/Inventati <debian@autistici.org>
-Build-Depends: debhelper (>= 10~), golang-any (>= 1.11), dh-golang
+Build-Depends: debhelper (>= 12~), golang-any (>= 1.11), dh-golang
 Standards-Version: 3.9.6
 
 Package: acmeserver

debian/rules

@@ -10,8 +10,8 @@ export DH_GOLANG_EXCLUDES = vendor
 override_dh_auto_install:
 	dh_auto_install -- --no-source
 
-override_dh_systemd_enable:
-	dh_systemd_enable --no-enable
+override_dh_installsystemd:
+	dh_installsystemd --no-enable
 
-override_dh_systemd_start:
-	dh_systemd_start --no-start
+override_dh_installsystemd:
+	dh_installsystemd --no-start