Update actions/checkout action to v4

[renovate]

This PR contains the following updates:

Package	Type	Update	Change
actions/checkout	action	major	v3 -> v4

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Release Notes

actions/checkout (actions/checkout)

v4

Compare Source

• Support fetching without the --progress option
• Update to node20

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Configuration

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[yegor256]

@rultor please, try to merge, since 5 checks have passed

[rultor]

@rultor please, try to merge, since 5 checks have passed

@yegor256 OK, I'll try to merge now. You can check the progress of the merge here

[rultor]

@rultor please, try to merge, since 5 checks have passed

@renovate[bot] @yegor256 Oops, I failed. You can see the full log here (spent 17s)

+ set -e
+ set -o pipefail
++ dirname ./run.sh
+ cd .
+ echo 799061
+ echo '2.0-SNAPSHOT BUILD'
2.0-SNAPSHOT BUILD
+ date
Tue 05 Sep 2023 05:37:23 AM CEST
+ uptime
 05:37:23 up 285 days, 10:15,  0 users,  load average: 2.08, 1.83, 1.76
+ cat
.rultor.yml in zerocracy/home doesn't allow zold-io/blog.zold.io to use its assets (there are 126 friends), see http://doc.rultor.com/reference.html#assets
+ exit -1
'cid' file is absent, most probably the Docker container wasn't started correctly