Bump actions/checkout from 4 to 5 #480

Job	Run time
ruby-versions / Generate Ruby versions	4s
ubuntu-24.04 3.0	20s
ubuntu-24.04 2.7	44s
ubuntu-24.04 3.4	16s
ubuntu-24.04 3.2	14s
ubuntu-24.04 head	24s
ubuntu-24.04 debug	30s
ubuntu-22.04 3.0	14s
ubuntu-24.04 3.1	14s
ubuntu-22.04 3.1	16s
ubuntu-24.04 3.3	14s
ubuntu-22.04 3.2	20s
ubuntu-24.04 truffleruby-head	28s
ubuntu-22.04 3.4	19s
ubuntu-24.04 jruby-head	1m 11s
ubuntu-22.04 debug	30s
ubuntu-22.04 2.7	43s
ubuntu-22.04 3.3	21s
ubuntu-22.04 head	27s
ubuntu-22.04 truffleruby-head	29s
ubuntu-22.04 jruby-head	1m 14s
	9m 32s

Provide feedback