!7 Add buildRequires systemd

From: @jxy_git 
Reviewed-by: @yangzhao_kl 
Signed-off-by: @yangzhao_kl

alertmanager.spec

@@ -2,18 +2,18 @@
 
 Name:    alertmanager
 Version: 0.21.0
-Release: 4
+Release: 5
 Summary: Prometheus Alertmanager.
 License: ASL 2.0
 URL:     https://github.com/prometheus/%{name}
 
-
 Source0: https://github.com/prometheus/%{name}/archive/refs/tags/v%{version}.tar.gz
 Source1: %{name}.service
 Source2: %{name}.default
 Source3: %{name}.yml
 
 BuildRequires: golang
+BuildRequires: systemd
 
 %{?systemd_requires}
 Requires(pre): shadow-utils
@@ -65,6 +65,9 @@ exit 0
 %dir %attr(755, prometheus, prometheus)%{_sharedstatedir}/prometheus
 
 %changelog
+* Fri Feb 03 2023 jiangxinyu <jiangxinyu@kylinos.cn> - 0.21.0-5
+- Add buildRequires systemd
+
 * Sat Jan 29 2022 yangzhao <yangzhao1@kylinos.cn> - 0.21.0-4
 - Build from source code