Bump actions/checkout from 2 to 2.3.4 (#22)

Bumps [actions/checkout](https://github.com/actions/checkout) from 2 to 2.3.4.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v2...v2.3.4)

Signed-off-by: dependabot[bot] <support@github.com>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

.github/workflows/build.yml

@@ -17,7 +17,7 @@ jobs:
     container: buildpack-deps:buster
     steps:
     - name: Checkout the repository
-      uses: actions/checkout@v2
+      uses: actions/checkout@v2.3.4
 
     - name: Setup go ${{ env.GOLANG_VERSION }}
       uses: actions/setup-go@v2

.github/workflows/golangci-lint.yml

@@ -9,7 +9,7 @@ jobs:
     name: lint
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v2.3.4
       - name: golangci-lint
         uses: golangci/golangci-lint-action@v2.5.2
         with: