Add new Unicode/Emoji version checks to spec/ruby/library/rbconfig

- Limit Unicode version 12.1.0 to Ruby versions 2.6.3 - 3.0
- Check that Ruby version 3.1 has Unicode version 13.0.0
- Limit Unicode Emoji version 12.1 to Ruby versions 2.7 - 3.0
- Check that Ruby version 3.1 has Unicode Emoji version 13.0

spec/ruby/library/rbconfig/unicode_emoji_version_spec.rb

@@ -14,9 +14,15 @@ describe "RbConfig::CONFIG['UNICODE_EMOJI_VERSION']" do
     end
   end
 
-  ruby_version_is "2.7" do
+  ruby_version_is "2.7"..."3.0" do
     it "is 12.1 for Ruby 2.7" do
       RbConfig::CONFIG['UNICODE_EMOJI_VERSION'].should == "12.1"
     end
   end
+
+  ruby_version_is "3.1" do
+    it "is 13.0 for Ruby 3.1" do
+      RbConfig::CONFIG['UNICODE_EMOJI_VERSION'].should == "13.0"
+    end
+  end
 end

spec/ruby/library/rbconfig/unicode_version_spec.rb

@@ -20,9 +20,15 @@ describe "RbConfig::CONFIG['UNICODE_VERSION']" do
     end
   end
 
-  ruby_version_is "2.6.3" do
-    it "is 12.1.0 for Ruby 2.6.3+ and Ruby 2.7" do
+  ruby_version_is "2.6.3"..."3.0" do
+    it "is 12.1.0 for Ruby 2.6.3+, Ruby 2.7, and Ruby 3.0" do
       RbConfig::CONFIG['UNICODE_VERSION'].should == "12.1.0"
     end
   end
+
+  ruby_version_is "3.1" do
+    it "is 13.0.0 for Ruby 3.1" do
+      RbConfig::CONFIG['UNICODE_VERSION'].should == "13.0.0"
+    end
+  end
 end