Bump actions/checkout from 3 to 4

Bumps [actions/checkout](https://github.com/actions/checkout) from 3 to 4.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v3...v4)

---
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/site.yml

@@ -15,7 +15,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
 
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
 
       - name: Get Hugo and Theme
         run: |

.github/workflows/test.yml

@@ -24,7 +24,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout code
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - id: go-version-matrix
         run: |
           go_version="$(awk '/^go/{print $2}' go.mod)"
@@ -51,7 +51,7 @@ jobs:
       - uses: actions/setup-python@v4
       - name: Setup go
         run: curl -sL https://github.com/raw/maxatome/install-go/v3.3/install-go.pl | perl - ${{ needs.DetermineVersion.outputs.go_version }} $HOME
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: actions/cache@v3
         with:
           path: |
@@ -74,7 +74,7 @@ jobs:
       - name: Setup go
         run: curl -sL https://github.com/raw/maxatome/install-go/v3.3/install-go.pl | perl - ${{ needs.DetermineVersion.outputs.go_version }} $HOME
       - name: Checkout code
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - uses: actions/cache@v3
         with:
           path: |
@@ -96,7 +96,7 @@ jobs:
       - name: Setup go
         run: curl -sL https://github.com/raw/maxatome/install-go/v3.3/install-go.pl | perl - ${{ needs.DetermineVersion.outputs.go_version }} $HOME
       - name: Checkout code
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - uses: actions/cache@v3
         with:
           path: |
@@ -123,7 +123,7 @@ jobs:
         shell: bash
         run: curl -sL https://github.com/raw/maxatome/install-go/v3.3/install-go.pl | perl - ${{ matrix.go }} $HOME
       - name: Checkout code
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - uses: actions/cache@v3
         with:
           path: |