gnucash-docs stable: Update actions/checkout to v3 in all actions.

[John Ralls]

Updated	 via  https://github.com/Gnucash/gnucash-docs/commit/98a176d5 (commit)
	from  https://github.com/Gnucash/gnucash-docs/commit/51f9e69f (commit)



commit 98a176d508852c9f0295c3fc19141bf6dd686a11
Author: John Ralls <jralls at ceridwen.us>
Date:   Tue Aug 1 14:13:08 2023 -0700

    Update actions/checkout to v3 in all actions.



Summary of changes:
 .github/workflows/dist-check.yml   | 2 +-
 .github/workflows/html-ubuntu.yml  | 2 +-
 .github/workflows/other-ubuntu.yml | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)