Bump actions/checkout from 2 to 3

Bumps [actions/checkout](https://github.com/actions/checkout) from 2 to 3.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v2...v3)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

.github/workflows/main.yml

@@ -8,7 +8,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
 
       - name: Set up Node
         uses: actions/setup-node@v2

.github/workflows/screenshot-bot.yml

@@ -20,7 +20,7 @@ jobs:
         - 3300:3300
         options: --health-cmd "mysqladmin ping -h localhost" --health-interval 10s --health-timeout 5s --health-retries 5
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - name: Use Ruby
         uses: actions/setup-ruby@v1
         with: