convert GPLv3+ license to SPDX

This is part of https://fedoraproject.org/wiki/Changes/SPDX_Licenses_Phase_4

proxyfuzz.spec

@@ -1,9 +1,10 @@
 Name:		proxyfuzz	
 Version:	20190404
-Release:	26%{?dist}
+Release:	27%{?dist}
 Summary:	Man-in-the-middle non-deterministic network fuzzer
 
-License:	GPLv3+
+# Automatically converted from old format: GPLv3+ - review is highly recommended.
+License:	GPL-3.0-or-later
 URL:		https://github.com/SECFORCE
 Source0:	proxyfuzz.py
 Source1:	README-Fedora
@@ -44,6 +45,9 @@ install -m 755 -p proxyfuzz.py ${RPM_BUILD_ROOT}/%{_sbindir}/proxyfuzz
 
 
 %changelog
+* Thu Jul 25 2024 Miroslav Suchý <msuchy@redhat.com> - 20190404-27
+- convert license to SPDX
+
 * Fri Jul 19 2024 Fedora Release Engineering <releng@fedoraproject.org> - 20190404-26
 - Rebuilt for https://fedoraproject.org/wiki/Fedora_41_Mass_Rebuild