ci: bump actions/setup-python from 5 to 6 (strands-agents#796)

Bumps [actions/setup-python](https://github.com/actions/setup-python) from 5 to 6.
- [Release notes](https://github.com/actions/setup-python/releases)
- [Commits](actions/setup-python@v5...v6)

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

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

Author: dependabot[bot]

.github/workflows/integration-test.yml

@@ -57,7 +57,7 @@ jobs:
           ref: ${{ github.event.pull_request.head.sha }} # Pull the commit from the forked repo
           persist-credentials: false  # Don't persist credentials for subsequent actions
       - name: Set up Python
-        uses: actions/setup-python@v5
+        uses: actions/setup-python@v6
         with:
           python-version: '3.10'
       - name: Install dependencies

.github/workflows/pypi-publish-on-release.yml

@@ -27,7 +27,7 @@ jobs:
         persist-credentials: false
 
     - name: Set up Python
-      uses: actions/setup-python@v5
+      uses: actions/setup-python@v6
       with:
         python-version: '3.10'
 

.github/workflows/test-lint.yml

@@ -56,7 +56,7 @@ jobs:
           ref: ${{ inputs.ref }}  # Explicitly define which commit to check out
           persist-credentials: false  # Don't persist credentials for subsequent actions
       - name: Set up Python
-        uses: actions/setup-python@v5
+        uses: actions/setup-python@v6
         with:
           python-version: ${{ matrix.python-version }}
       - name: Install dependencies
@@ -79,7 +79,7 @@ jobs:
           persist-credentials: false
 
       - name: Set up Python
-        uses: actions/setup-python@v5
+        uses: actions/setup-python@v6
         with:
           python-version: '3.10'
           cache: 'pip'