!8 [sync] PR-7: Add buildrequire graphviz

From: @openeuler-sync-bot 
Reviewed-by: @small_leek 
Signed-off-by: @small_leek

libsigc++20.spec

@@ -1,13 +1,13 @@
 Name:           libsigc++20
 Version:        2.10.6
-Release:        1
+Release:        2
 Summary:        Typesafe signal framework for C++
 License:        LGPLv2+
 URL:            https://github.com/libsigcplusplus/libsigcplusplus
 Source0:        https://github.com/libsigcplusplus/libsigcplusplus/releases/download/%{version}/libsigc++-%{version}.tar.xz
 
 BuildRequires:  docbook-style-xsl
-BuildRequires:  doxygen
+BuildRequires:  doxygen graphviz
 BuildRequires:  gcc-c++
 BuildRequires:  libxslt
 BuildRequires:  m4
@@ -75,6 +75,9 @@ This package contains the full API documentation for %{name}.
 
 
 %changelog
+* Thu Jan 6 2022 liyanan <liyanan32@huawei.com> - 2.10.6-2
+- Add buildrequire graphviz
+
 * Fri Jun 18 2021 weijin deng <weijin.deng@turbolinux.com.cn> - 2.10.6-1
 - Upgrade to 2.10.6