Bump actions/checkout from 3 to 4 (#36)

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

.github/workflows/zsh-n.yml

@@ -26,7 +26,7 @@ jobs:
       matrix: ${{ steps.set-matrix.outputs.matrix }}
     steps:
       - name: ⤵️ Check out code from GitHub
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - name: "⚡ Set matrix output"
         id: set-matrix
         run: |
@@ -41,7 +41,7 @@ jobs:
       matrix: ${{ fromJSON(needs.zsh-matrix.outputs.matrix) }}
     steps:
       - name: ⤵️ Check out code from GitHub
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - name: "⚡ Install dependencies"
         run: sudo apt update && sudo apt-get install -yq zsh
       - name: "⚡ zsh -n: ${{ matrix.file }}"

.github/workflows/zunit.yml

@@ -25,7 +25,7 @@ jobs:
     name: 🧪 ZUnit Mac
     runs-on: macos-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: 📚 Get ZUnit
         run: |
           mkdir bin
@@ -47,7 +47,7 @@ jobs:
     name: 🧪 ZUnit Linux
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: ℹ️ Setup linux dependencies
         run: |
           sudo apt update