!31 [sync] PR-30: upgrade libpq to 15.6

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

libpq.spec

@@ -1,5 +1,5 @@
 Name: libpq
-Version: 15.5
+Version: 15.6
 Release: 1
 Summary: PostgreSQL client library
 License: PostgreSQL
@@ -14,7 +14,7 @@ Patch0004: add-loongarch-support.patch
 BuildRequires: gcc glibc-devel bison flex gawk zlib-devel openssl-devel
 BuildRequires: krb5-devel openldap-devel gettext multilib-rpm-config
 
-Obsoletes: postgresql-libs < 14
+Obsoletes: postgresql-libs < 15
 Provides: postgresql-libs = %{version}-%{release}
 
 %description
@@ -28,7 +28,7 @@ or interface.
 Summary: Development files for building PostgreSQL client tools
 Requires: libpq%{?_isa} = %{version}-%{release}
 Provides: postgresql-devel = %{version}-%{release}
-Obsoletes: postgresql-devel < 14
+Obsoletes: postgresql-devel < 15
 
 %description devel
 The development package of libpq
@@ -80,6 +80,9 @@ cat pg_config-15.lang >>libpq-devel.lst
 %_libdir/pkgconfig/libpq.pc
 
 %changelog
+* Wed Apr 3 2024 xiejing <xiejing@kylinos.cn> - 15.6-1
+- upgrade libpq to 15.6
+
 * Mon Nov 20 2023 dillon chen<dillon.chen@gmail.com> - 15.5-1
 - upgrade libpq to 15.5
 - CVE-2023-5868/5869/5870