add BR for hostname

... to avoid the following build-time message:

./configure: line 7463: hostname: command not found

coreutils.spec

@@ -1,7 +1,7 @@
 Summary: A set of basic GNU tools commonly used in shell scripts
 Name:    coreutils
 Version: 8.28
-Release: 9999.1%{?dist}
+Release: 9999.2%{?dist}
 License: GPLv3+
 Group:   System Environment/Base
 Url:     https://www.gnu.org/software/coreutils/
@@ -100,6 +100,7 @@ BuildRequires: automake
 BuildRequires: bison
 BuildRequires: gettext-devel
 BuildRequires: gmp-devel
+BuildRequires: hostname
 BuildRequires: libacl-devel
 BuildRequires: libattr-devel
 BuildRequires: libcap-devel