Dependabot Github Actions: 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/ci.yml

@@ -18,7 +18,7 @@ jobs:
         python-version: ["3.9", "3.10", "3.11", "3.12"]
 
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
 
     - name: Set up Python ${{ matrix.python-version }}
       uses: actions/setup-python@v5
@@ -48,7 +48,7 @@ jobs:
   lint:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
 
     - name: Set up Python
       uses: actions/setup-python@v5

.github/workflows/unit_build_and_push.yml

@@ -16,7 +16,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       - name: Set tag output
         id: vars
         # Create the output from the tag and strip "v" from tag

.github/workflows/unit_python_tests.yml

@@ -14,7 +14,7 @@ jobs:
       # comments (to avoid publishing multiple comments in the same PR)
       contents: write
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - name: Install dependencies
         run: |
           python3 -m pip install --upgrade pip

.github/workflows/unit_ruff.yml

@@ -6,7 +6,7 @@ jobs:
   ruff:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: chartboost/ruff-action@v1
         with:
           args: --ignore E501