chore(deps): 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/build.yml

@@ -33,7 +33,7 @@ jobs:
           go-version: ${{ matrix.go-version }}
 
       - name: Checkout code
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Test
         run: make test

.github/workflows/doctests.yaml

@@ -34,7 +34,7 @@ jobs:
           go-version: ${{ matrix.go-version }}
 
       - name: Checkout code
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Test doc examples
         working-directory: ./doctests

.github/workflows/golangci-lint.yml

@@ -21,6 +21,6 @@ jobs:
     name: lint
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: golangci-lint
         uses: golangci/golangci-lint-action@v3

.github/workflows/spellcheck.yml

@@ -6,7 +6,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - name: Check Spelling
         uses: rojopolis/spellcheck-github-actions@0.33.1
         with: