Drop tidy dependency.

There are some non-essential tests skipped due to missing tidy, but in
exchange this helps to reduce dependency chain a bit.

Related: rhbz#1951246

rubygem-kramdown.spec

@@ -3,7 +3,7 @@
 
 Name: rubygem-%{gem_name}
 Version: 2.3.1
-Release: 3%{?dist}
+Release: 4%{?dist}
 Summary: Fast, pure-Ruby Markdown-superset converter
 
 License:	MIT
@@ -15,8 +15,6 @@ BuildRequires:	rubygem(minitest) >= 5
 BuildRequires:	rubygem(rexml)
 BuildRequires:	rubygem(rouge) >= 3.26.0
 BuildRequires:	rubygem(test-unit)
-# Some additional dependency for check
-BuildRequires:	tidy
 Requires:	ruby(release)
 Requires:	ruby(rubygems)
 BuildArch: noarch
@@ -102,6 +100,10 @@ popd
 %doc	%{gem_docdir}
 
 %changelog
+* Tue May 25 2021 Vít Ondruch <vondruch@redhat.com> - 2.3.1-4
+- Drop `tidy` dependency.
+  Related: rhbz#1951246
+
 * Thu May 13 2021 Vít Ondruch <vondruch@redhat.com> - 2.3.1-3
 - Drop Latex test cases and disable stringex dependency.
   Resolves: rhbz#1951246