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/build-test.yml

@@ -10,7 +10,7 @@ jobs:
       - uses: actions/setup-go@v2
         with:
           go-version: 1.13.x
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - name: Build
         run: go build .
       - name: Test