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>

Author: dependabot[bot]

.github/workflows/compile-examples.yml

@@ -18,7 +18,7 @@ jobs:
           - arduino:renesas_uno:unor4wifi
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: arduino/compile-sketches@v1
         with:
           github-token: ${{ secrets.GITHUB_TOKEN }}
@@ -39,7 +39,7 @@ jobs:
           #- esp32:esp32:esp32h2
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: arduino/compile-sketches@v1
         with:
           github-token: ${{ secrets.GITHUB_TOKEN }}

.github/workflows/spell-check.yml

@@ -8,7 +8,7 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Spell check
         uses: arduino/actions/libraries/spell-check@master

.github/workflows/sync-labels.yml

@@ -27,7 +27,7 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Download JSON schema for labels configuration file
         id: download-schema
@@ -105,7 +105,7 @@ jobs:
           echo "::set-output name=flag::--dry-run"
 
       - name: Checkout repository
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Download configuration files artifact
         uses: actions/download-artifact@v3