TL;DR

Node 12 is deprecated

Detailed design

• Cut a release with current features with node12 support
• Update action.yml to uses: 'node16'
• Update all tests to use 16 in the matrix
• Update actions/checkout@v2 -> actions/checkout@v3 everywhere
• Update README to note node 16 requirement for self-hosted runners (example)
• Cut a release with node16 support

Additional information

No response