Update GH Actions

[renovate]

This PR contains the following updates:

Package	Type	Update	Change
actions/checkout	action	major	v4 -> v5
mysql	service	minor	9.2 -> 9.4
mysql	docker	minor	9.2 -> 9.4
postgres	service	minor	17.2-alpine -> 17.6-alpine
postgres	docker	minor	17.2-alpine -> 17.6-alpine

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Release Notes

actions/checkout (actions/checkout)

v5

Compare Source

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[straight-shoota]

This change seems to break something: https://github.com/crystal-lang/test-ecosystem/actions/runs/14466278922/job/40569272939#step:13:11

I suppose we should probably remove this workflow entirely. The new one is more efficient, and we don't really use the old one any more.