Upgrade to actions/checkout@v3
Upgrade to actions/checkout@v3

for fix deprecation warning

> 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: actions/checkout, actions/checkout

https://github.com/itamae-kitchen/itamae/actions/runs/3246590133

itamae-kitchen/itamae,itamae-kitchen/itamae