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] <support@github.com>

Author: dependabot[bot]

.github/workflows/ci.yml

@@ -31,7 +31,7 @@ jobs:
             rust: nightly
             experimental: true
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - name: Install rust
         uses: actions-rs/toolchain@v1
         with:
@@ -61,7 +61,7 @@ jobs:
     needs:
       - build
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - run: pip3 install -U tomlq
       - name: Install rust
         uses: actions-rs/toolchain@v1