update actions/cache + actions/checkout in GitHub Actions to v3

[striezel]

Updates the actions/checkout and actions/cache actions used in the GitHub Actions workflow to their newest version.

Changes in actions/cache:

3.0.0

• Updated minimum runner version support from node 12 -> node 16

3.0.1

• Added support for caching from GHES 3.5.
• Fixed download issue for files > 2GB during restore.

3.0.2

• Added support for dynamic cache size cap on GHES.

3.0.3

• Fixed avoiding empty cache save when no files are available for caching. (issue)

Changes in actions/checkout:

v3.0.2

• Add input set-safe-directory

v3.0.1

• Fixed an issue where checkout failed to run in container jobs due to the new git setting safe.directory
• Bumped various npm package versions

v3.0.0

• Update to node 16

As far as I can tell this should all be backwards compatible, so I do not expect any breakage.

[lemire]

Looks good

[striezel]

Indeed. All checks passed with the newer versions of actions/checkout and actions/cache.

[lemire]

Merging.