ルビィ 3

はい

$ rbenv install -l
2.5.8
2.6.6
2.7.2
3.0.0
jruby-9.2.14.0
mruby-2.1.2
rbx-5.0
truffleruby-20.3.0
truffleruby+graalvm-20.3.0

Only latest stable releases for each Ruby implementation are shown.
Use 'rbenv install --list-all / -L' to show all local versions.

$ rbenv install 3.0.0 

（略）

$ rbenv global 3.0.0

$ ruby --version
ruby 3.0.0p0 (2020-12-25 revision 95aff21468) [x86_64-darwin20]