Run tests against Ruby 3.5 and JRuby 10.0

These have been released since I last did any work on this repo. Let's
get our tests running on them!

Signed-off-by: Chris Sinjakli <chris@sinjakli.co.uk>

Author: Sinjo

.circleci/config.yml

@@ -50,6 +50,7 @@ workflows:
             - cimg/ruby:3.2
             - cimg/ruby:3.3
             - cimg/ruby:3.4
+            - cimg/ruby:4.0
             # We've switched to JRuby's own Docker image as CircleCI decided to
             # stop supporting it when they deprecated their legacy images. For
             # some reason, the official JRuby image for 9.1 fails with an
@@ -61,3 +62,4 @@ workflows:
             - jruby:9.2
             - jruby:9.3
             - jruby:9.4
+            - jruby:10.0