deps(gha): bump actions/checkout from 5 to 6

Bumps [actions/checkout](https://github.com/actions/checkout) from 5 to 6.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v5...v6)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

.github/workflows/check-spelling.yml

@@ -26,7 +26,7 @@ jobs:
 
     steps:
       - name: 🤘 Checkout Code
-        uses: actions/checkout@v5 # https://github.com/actions/checkout
+        uses: actions/checkout@v6 # https://github.com/actions/checkout
 
       - name: 🔽 Install Dependencies
         run: sudo npm install -g cspell

.github/workflows/release.yml

@@ -63,7 +63,7 @@ jobs:
           docker-images: false
 
       - name: 🤘 Checkout Code
-        uses: actions/checkout@v5 # https://github.com/actions/checkout
+        uses: actions/checkout@v6 # https://github.com/actions/checkout
 
       - name: 🔍 Run hadolint
         uses: hadolint/hadolint-action@v3.3.0 # https://github.com/hadolint/hadolint-action
@@ -345,7 +345,7 @@ jobs:
     steps:
 
       - name: 🤘 Checkout gh-pages branch
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
         with:
           ref: gh-pages
           fetch-depth: 1