Update referenced actions/checkout version in workflows to fix update-main-version.yml

[jww3]

Based on this error text:

To https://github.com/actions/checkout
 ! [remote rejected] v4 -> v4 (refusing to allow a GitHub App to 
     create or update workflow `.github/workflows/test.yml` 
     without `workflows` permission)
error: failed to push some refs to 'https://github.com/actions/checkout'

source

it seems it was inappropriate to update test.yml to reference a v4* tag.

This PR reverts that change.