drop perl Email::Valid dep on RHEL (#2166718)

The git send-email command uses Email::Valid to check addresses.  If
Email::Valid is not present, it falls back to a more basic regex match
(which is not nearly as thorough as the checks Email::Valid performs).

While Fedora (and EPEL 7/8 provide perl-Email-Valid, RHEL does not and
does not wish to add the dependency.  Make it easier for RHEL to fork &
sync from us by making the dependency conditional.

References:
https://bugzilla.redhat.com/2020487
https://bugzilla.redhat.com/2046203
http://public-inbox.org/git/20220620004427.3586240-1-trawets@amazon.com/T/#u
4414f61 (add more git-email perl dependencies, 2021-11-13)

git.spec

@@ -81,7 +81,7 @@
 
 Name:           git
 Version:        2.39.1
-Release:        1%{?rcrev}%{?dist}.1
+Release:        2%{?rcrev}%{?dist}
 Summary:        Fast Version Control System
 License:        BSD-3-Clause AND GPL-2.0-only AND GPL-2.0-or-later AND LGPL-2.1-or-later AND MIT
 URL:            https://git-scm.com/
@@ -390,7 +390,10 @@ BuildArch:      noarch
 Requires:       git = %{version}-%{release}
 Requires:       perl(Authen::SASL)
 Requires:       perl(Cwd)
+%if ! 0%{?rhel}
+# RHEL lacks perl-Email-Valid (rhbz#2166718)
 Requires:       perl(Email::Valid)
+%endif
 Requires:       perl(File::Spec)
 Requires:       perl(File::Spec::Functions)
 Requires:       perl(File::Temp)
@@ -1032,6 +1035,9 @@ rmdir --ignore-fail-on-non-empty "$testdir"
 %{?with_docs:%{_pkgdocdir}/git-svn.html}
 
 %changelog
+* Fri Feb 03 2023 Todd Zullinger <tmz@pobox.com> - 2.39.1-2
+- drop perl Email::Valid dep on RHEL (#2166718)
+
 * Thu Jan 19 2023 Fedora Release Engineering <releng@fedoraproject.org> - 2.39.1-1.1
 - Rebuilt for https://fedoraproject.org/wiki/Fedora_38_Mass_Rebuild