Bump actions/checkout from 2.3.5 to 2.4.0

Bumps [actions/checkout](https://github.com/actions/checkout) from 2.3.5 to 2.4.0.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v2.3.5...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/ci.yaml

@@ -23,7 +23,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - name: checkout
-      uses: actions/checkout@v2.3.5
+      uses: actions/checkout@v2.4.0
     - uses: actions/setup-go@v2
       with:
         go-version: '1.15' # The Go version to download (if necessary) and use.

.github/workflows/release.yaml

@@ -36,7 +36,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout code
-        uses: actions/checkout@v2.3.5
+        uses: actions/checkout@v2.4.0
 
       - name: kubebuilder
         run: make kubebuilder KUBEBUILDER_DIR=${KUBEBUILDER_DIR} # we use this dir because /usr/local/kubebuilder is protected