v0.68.0

Updated runs-on confguration @Nuru (#140)

## what

• Update Runs-On configuration
• Remove s3-cache setting from all runners
• Add comments

why

• Better reflect Cloud Posse usage
• Magic s3-cache breaks artifact up/downloads if not combined with runs-on/action, so it should be set per-job, not by default.
• Compare to GitHub hosted runners
• Caution against blindly adopting these definitions in other circumstances