Bump actions/checkout from 5 to 6 (#742)

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

Author: dependabot[bot]

.github/workflows/ci-format.yaml

@@ -12,7 +12,7 @@ jobs:
     name: Format
     runs-on: ubuntu-22.04
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
     - uses: actions/setup-python@v6
       with:
         python-version: 3.10.6

.github/workflows/ci-humble.yaml

@@ -42,10 +42,10 @@ jobs:
     steps:
     - name: Checkout code
       if: github.event_name != 'schedule'
-      uses: actions/checkout@v5
+      uses: actions/checkout@v6
     - name: Checkout code for scheduled workflow
       if: github.event_name == 'schedule'
-      uses: actions/checkout@v5
+      uses: actions/checkout@v6
       with:
         ref: humble
     - name: Checkout ros2_control framework for semi-binary builds

.github/workflows/ci-jazzy.yaml

@@ -30,10 +30,10 @@ jobs:
     steps:
     - name: Checkout code
       if: github.event_name != 'schedule'
-      uses: actions/checkout@v5
+      uses: actions/checkout@v6
     - name: Checkout code for scheduled workflow
       if: github.event_name == 'schedule'
-      uses: actions/checkout@v5
+      uses: actions/checkout@v6
       with:
         ref: jazzy
     - name: Checkout ros2_control framework for semi-binary builds

.github/workflows/ci-kilted.yaml

@@ -30,10 +30,10 @@ jobs:
     steps:
     - name: Checkout code
       if: github.event_name != 'schedule'
-      uses: actions/checkout@v5
+      uses: actions/checkout@v6
     - name: Checkout code for scheduled workflow
       if: github.event_name == 'schedule'
-      uses: actions/checkout@v5
+      uses: actions/checkout@v6
       with:
         ref: kilted
     - name: Checkout ros2_control framework for semi-binary builds

.github/workflows/ci-rolling.yaml

@@ -31,7 +31,7 @@ jobs:
     container:
       image: ghcr.io/ros-controls/ros:${{ matrix.ros-distro }}-ubuntu${{ matrix.ros-repo-packages }}
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
     - name: Checkout ros2_control framework for semi-binary builds
       if: ${{ matrix.upstream-repos != '' }}
       run: vcs import --input ${{ matrix.upstream-repos }}