Bump actions/checkout from 2 to 4

Bumps [actions/checkout](https://github.com/actions/checkout) from 2 to 4.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v2...v4)

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

Signed-off-by: dependabot[bot] <[email protected]>

.github/workflows/docker.yml

@@ -18,7 +18,7 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - name: Log in to the Container registry
         uses: docker/login-action@v2
         with:

.github/workflows/humble.yml

@@ -19,7 +19,7 @@ jobs:
     env:
       CCACHE_DIR: "${{ github.workspace }}/.ccache"
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - uses: actions/cache@v4
         with:
           path: ${{ env.CCACHE_DIR }}

.github/workflows/humble_documentation.yml

@@ -19,7 +19,7 @@ jobs:
     # Steps represent a sequence of tasks that will be executed as part of the job
     steps:
       # Checks-out your repository under $GITHUB_WORKSPACE, so your job can access it
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
 
       - name: Install dependencies
         run: |

.github/workflows/iron.yml

@@ -19,7 +19,7 @@ jobs:
     env:
       CCACHE_DIR: "${{ github.workspace }}/.ccache"
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - uses: actions/cache@v4
         with:
           path: ${{ env.CCACHE_DIR }}

.github/workflows/iron_documentation.yml

@@ -19,7 +19,7 @@ jobs:
     # Steps represent a sequence of tasks that will be executed as part of the job
     steps:
       # Checks-out your repository under $GITHUB_WORKSPACE, so your job can access it
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
 
       - name: Install dependencies
         run: |

.github/workflows/rolling_documentation.yml

@@ -19,7 +19,7 @@ jobs:
     # Steps represent a sequence of tasks that will be executed as part of the job
     steps:
       # Checks-out your repository under $GITHUB_WORKSPACE, so your job can access it
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
 
       - name: Install dependencies
         run: |