Fix GitHub Actions issue

[mathomp4]

Description

This is an update to the GitHub Actions in MAPL to try and fix an issue I saw when I accidentally pressed the "Update branch" button in the Tutoral PR #1586 (sorry @bena-nasa !)

It seems to be something solved in checkout v3 per actions/checkout#762, so we try that.

ETA: Nope. It looks like that doesn't spread down the tree of steps. So we go old school and run:

git config --global --add safe.directory '*'

There's no force like brute force!

Related Issue

Motivation and Context

Let's the GitHub Actions run again!

How Has This Been Tested?

The CI will test it for me.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Trivial change (affects only documentation or cleanup)

Checklist:

• I have tested this change with a run of GEOSgcm (if non-trivial)
• I have added one of the required labels (0 diff, 0 diff trivial, 0 diff structural, non 0-diff)
• I have updated the CHANGELOG.md accordingly following the style of Keep a Changelog