spec/ruby/library/matrix/: Change the version guard to 3.0.2

[Bug #17521] is not backported to 3.0.1.

Author: mame

spec/ruby/library/matrix/exponent_spec.rb

@@ -34,7 +34,7 @@
       end
     end
 
-    ruby_version_is '3.0.1' do # https://bugs.ruby-lang.org/issues/17521
+    ruby_version_is '3.0.2' do # https://bugs.ruby-lang.org/issues/17521
       describe "that is 0" do
         it "returns the identity for square matrices" do
           m = Matrix[ [1, 1], [1, 1] ]