This PR will fix CI failures and improve Ruby 3.3 support.
Remove bundler installation
It installs bundler without specifying the version in CI. But, it installs bundler which does not work with old Ruby, and it causes failure. So, this patch remove bundler installation and uses bundler bundled in Ruby.
Fix failure with Ruby 3.3
The method of getting pointers from TypedData structure has changed since Ruby 3.3. This PR follows that.
This PR will fix CI failures and improve Ruby 3.3 support.
Remove bundler installation
Fix failure with Ruby 3.3