Use < 3 as suggested during review #21

Job	Run time
ruby-versions / Generate Ruby versions	2s
ubuntu-24.04 2.7	40s
ubuntu-24.04 3.0	9s
ubuntu-24.04 3.1	10s
ubuntu-24.04 3.2	15s
ubuntu-24.04 3.3	11s
ubuntu-24.04 debug	18s
ubuntu-24.04 head	11s
ubuntu-24.04 jruby-head	25s
ubuntu-24.04 truffleruby-head	24s
ubuntu-22.04 2.7	35s
ubuntu-22.04 3.0	9s
ubuntu-22.04 3.1	12s
ubuntu-22.04 3.2	18s
ubuntu-22.04 3.3	9s
ubuntu-22.04 debug	17s
ubuntu-22.04 head	9s
ubuntu-22.04 jruby-head	30s
ubuntu-22.04 truffleruby-head	23s
ubuntu-20.04 2.7	34s
ubuntu-20.04 3.0	8s
ubuntu-20.04 3.1	12s
ubuntu-20.04 3.2	15s
ubuntu-20.04 3.3	10s
ubuntu-20.04 debug	23s
ubuntu-20.04 head	11s
ubuntu-20.04 jruby-head	26s
ubuntu-20.04 truffleruby-head	27s
	8m 13s

Provide feedback