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>

.github/workflows/coverage.yml

@@ -10,7 +10,7 @@ jobs:
       image: xd009642/tarpaulin:develop-nightly
       options: --security-opt seccomp=unconfined
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - name: Generate code coverage
         run: |
           cargo +nightly tarpaulin --verbose --all-features --workspace --timeout 120 --run-types Doctests --run-types Tests --out Xml