Update Node.js runtime from 12 to 16

[Gene Wood]

This action currently uses Node.js 12 which went out of support April 2022. GitHub now shows this warning when rubocop-problem-matchers-action runs

Node.js 12 actions are deprecated. For more information see: https://github.blog/changelog/2022-09-22-github-actions-all-actions-will-begin-running-on-node16-instead-of-node12/. Please update the following actions to use Node.js 16: r7kamura/rubocop-problem-matchers-action@v1

Please update the runtime in the action to Node.js 16