Bump actions/checkout from 2.3.4 to 2.4.0

Bumps [actions/checkout](https://github.com/actions/checkout) from 2.3.4 to 2.4.0.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](https://github.com/actions/checkout/compare/v2.3.4...v2.4.0)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

.github/workflows/docker-build-and-push.yml

@@ -31,7 +31,7 @@ jobs:
     steps:
       -
         name: Checkout
-        uses: actions/checkout@v2.3.4
+        uses: actions/checkout@v2.4.0
       -
         # we need qemu and buildx so we can build multiple platforms later
         name: Set up QEMU

.github/workflows/linter.yml

@@ -38,7 +38,7 @@ jobs:
       # Checkout the code base #
       ##########################
       - name: Checkout Code
-        uses: actions/checkout@v2.3.4
+        uses: actions/checkout@v2.4.0
         with:
           # Full git history is needed to get a proper list of changed files within `super-linter`
           fetch-depth: 0