Bump actions/checkout from 4 to 6 (#34)

Bumps [actions/checkout](https://github.com/actions/checkout) from 4 to 6.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v4...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>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

.github/workflows/_test-package.yml

@@ -21,7 +21,7 @@ jobs:
       matrix:
         python-version: ["3.11", "3.12", "3.13"]
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
       - name: Set up Python ${{ matrix.python-version }}
         uses: actions/setup-python@v5

.github/workflows/ci.yml

@@ -40,7 +40,7 @@ jobs:
   docs-freshness:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
       - name: Set up Python 3.12
         uses: actions/setup-python@v5
@@ -78,7 +78,7 @@ jobs:
     runs-on: ubuntu-latest
     needs: [types, mcp-client, mcp-server, agentic-mcp-server, sdk]
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
       - name: Set up Python 3.12
         uses: actions/setup-python@v5

.github/workflows/codeql.yml

@@ -16,7 +16,7 @@ jobs:
       matrix:
         language: [python]
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
       - name: Initialize CodeQL
         uses: github/codeql-action/init@v4

.github/workflows/dependency-review.yml

@@ -11,7 +11,7 @@ jobs:
   dependency-review:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - uses: actions/dependency-review-action@v4
         with:
           fail-on-severity: high