Bump actions/checkout from 3 to 4

Bumps [actions/checkout](https://github.com/actions/checkout) from 3 to 4.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v3...v4)

---
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/autotag-releases.yml

@@ -15,7 +15,7 @@ jobs:
     permissions:
       contents: write
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: Get version from tag
         id: tag_name
         run: |

.github/workflows/ci.yml

@@ -29,7 +29,7 @@ jobs:
           "macos-latest",
         ]
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       # Test toolchain file support
       - name: Write rust-toolchain.toml
         run: |