spec: Quote words on both sides of string comparisons

With RPM 4.16, so-called "bare words" are no longer supported for
comparisons. Quoting on both sides works fine for all versions of
RPM and debbuild, so do that instead.

Author: Conan-Kudo

debbuild-macros.spec

@@ -6,7 +6,7 @@ Version:        0.0.4
 Release:        0%{?dist}
 Summary:        Various macros for extending debbuild functionality
 
-%if %{_vendor} == "debbuild"
+%if "%{_vendor}" == "debbuild"
 Group:          devel
 Packager:       debbuild developers <https://github.com/debbuild/debbuild>
 License:        MIT and LGPL-2.1+ and Apache-2.0 and GPL-2.0+