add a systemd timer to monthly clean cache (paccache -r)

Makefile

@@ -39,6 +39,10 @@ install:
 	install -Dm644 data/dbus/org.manjaro.pamac.conf $(sysconfdir)/dbus-1/system.d/org.manjaro.pamac.conf
 	install -Dm644 data/dbus/org.manjaro.pamac.service $(datadir)/dbus-1/system-services/org.manjaro.pamac.service
 	install -Dm644 data/systemd/pamac.service $(libdir)/systemd/system/pamac.service
+	install -Dm644 data/systemd/pamac-cleancache.service $(libdir)/systemd/system/pamac-cleancache.service
+	install -Dm644 data/systemd/pamac-cleancache.timer $(libdir)/systemd/system/pamac-cleancache.timer
+	mkdir -p $(libdir)/systemd/system/multi-user.target.wants
+	ln -srf $(libdir)/systemd/system/pamac-cleancache.timer $(libdir)/systemd/system/multi-user.target.wants
 	install -Dm744 data/networkmanager/99_update_pamac_tray $(sysconfdir)/NetworkManager/dispatcher.d/99_update_pamac_tray
 	install -Dm644 data/polkit/org.manjaro.pamac.policy $(datadir)/polkit-1/actions/org.manjaro.pamac.policy
 	install -Dm644 data/mime/x-alpm-package.xml $(datadir)/mime/packages/x-alpm-package.xml
@@ -66,6 +70,9 @@ uninstall:
 	rm -f $(sysconfdir)/dbus-1/system.d/org.manjaro.pamac.conf
 	rm -f $(datadir)/dbus-1/system-services/org.manjaro.pamac.service
 	rm -f $(libdir)/systemd/system/pamac.service
+	rm -f $(libdir)/systemd/system/pamac-cleancache.service
+	rm -f $(libdir)/systemd/system/pamac-cleancache.timer
+	rm -f $(libdir)/systemd/system/multi-user.target.wants/pamac-cleancache.timer
 	rm -f $(sysconfdir)/NetworkManager/dispatcher.d/99_update_pamac_tray
 	rm -f $(datadir)/polkit-1/actions/org.manjaro.pamac.policy
 	rm -f $(datadir)/mime/packages/x-alpm-package.xml

data/systemd/pamac-cleancache.service

+[Unit]
+Description=Clean packages cache
+
+[Service]
+Type=oneshot
+ExecStart=/usr/bin/paccache -rq

data/systemd/pamac-cleancache.timer

+[Unit]
+Description=Monthly clean packages cache
+
+[Timer]
+OnCalendar=monthly
+Persistent=true
+
+[Install]
+WantedBy=timers.target