Drop build-dep on dh-systemd by bumping compat to 10

Bullseye does not provide dh-systemd anymore, and it is enabled by
default with debhelper compat >= 10.

Signed-off-by: Emanuele Aina <emanuele.aina@collabora.com>

debian/compat

-9
+10

debian/control

@@ -8,7 +8,6 @@ Build-Depends:
  debhelper (>= 9),
  dh-apparmor,
  dh-autoreconf,
- dh-systemd,
  gobject-introspection,
  hotdoc-0.8 (>= 0.8),
  hotdoc-c-extension-0.8,

debian/rules

@@ -6,7 +6,7 @@ export DEB_BUILD_MAINT_OPTIONS = hardening=+all
 include /usr/share/dpkg/default.mk
 
 %:
-	dh $@ --with autoreconf,gir,systemd --parallel
+	dh $@ --with autoreconf,gir --parallel
 
 override_dh_auto_configure:
 	dh_auto_configure \