convert GPLv3 license to SPDX

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

java-runtime-decompiler.spec

@@ -1,8 +1,9 @@
 Summary: Application for extraction and decompilation of JVM byte code
 Name: java-runtime-decompiler
 Version: 9.1
-Release: 7%{?dist}
-License: GPLv3
+Release: 8%{?dist}
+# Automatically converted from old format: GPLv3 - review is highly recommended.
+License: GPL-3.0-only
 URL: https://github.com/pmikova/java-runtime-decompiler
 Source0: https://github.com/judovana/%{name}/archive/%{name}-%{version}.tar.gz
 Source1: %{name}
@@ -228,6 +229,9 @@ rm $RPM_BUILD_ROOT%{_sysconfdir}/%{name}/plugins/JdDecompilerWrapper.json
 %license LICENSE
 
 %changelog
+* Mon Jul 29 2024 Miroslav Suchý <msuchy@redhat.com> - 9.1-8
+- convert license to SPDX
+
 * Thu Jul 18 2024 Fedora Release Engineering <releng@fedoraproject.org> - 9.1-7
 - Rebuilt for https://fedoraproject.org/wiki/Fedora_41_Mass_Rebuild