chore(deps): bump the github-actions group with 4 updates

Bumps the github-actions group with 4 updates: [actions/download-artifact](https://github.com/actions/download-artifact), [actions/upload-artifact](https://github.com/actions/upload-artifact), [actions/github-script](https://github.com/actions/github-script) and [actions/checkout](https://github.com/actions/checkout).


Updates `actions/download-artifact` from 4 to 8
- [Release notes](https://github.com/actions/download-artifact/releases)
- [Commits](actions/download-artifact@v4...v8)

Updates `actions/upload-artifact` from 4 to 7
- [Release notes](https://github.com/actions/upload-artifact/releases)
- [Commits](actions/upload-artifact@v4...v7)

Updates `actions/github-script` from 6 to 8
- [Release notes](https://github.com/actions/github-script/releases)
- [Commits](actions/github-script@v6...v8)

Updates `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/download-artifact
  dependency-version: '8'
  dependency-type: direct:production
  update-type: version-update:semver-major
  dependency-group: github-actions
- dependency-name: actions/upload-artifact
  dependency-version: '7'
  dependency-type: direct:production
  update-type: version-update:semver-major
  dependency-group: github-actions
- dependency-name: actions/github-script
  dependency-version: '8'
  dependency-type: direct:production
  update-type: version-update:semver-major
  dependency-group: github-actions
- dependency-name: actions/checkout
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
  dependency-group: github-actions
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

.github/workflows/coverage-comment.yaml

@@ -18,22 +18,22 @@ jobs:
       github.event.workflow_run.conclusion == 'success'
     steps:
       - name: Download Coverage Artifacts
-        uses: actions/download-artifact@v4
+        uses: actions/download-artifact@v8
         with:
           run-id: ${{ github.event.workflow_run.id }}
           github-token: ${{ secrets.A2A_BOT_PAT }}
           name: coverage-data
 
       - name: Upload Coverage Report
         id: upload-report
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@v7
         with:
           name: coverage-report
           path: coverage/
           retention-days: 14
 
       - name: Post Comment
-        uses: actions/github-script@v6
+        uses: actions/github-script@v8
         env:
           ARTIFACT_URL: ${{ steps.upload-report.outputs.artifact-url }}
         with:

.github/workflows/unit-tests.yml

@@ -60,7 +60,7 @@ jobs:
       # Coverage comparison for PRs (only on Python 3.13 to avoid duplicate work)
       - name: Checkout Base Branch
         if: github.event_name == 'pull_request' && matrix.python-version == '3.13'
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
         with:
           ref: ${{ github.event.pull_request.base.ref || 'main' }}
           clean: true
@@ -73,7 +73,7 @@ jobs:
 
       - name: Checkout PR Branch (Restore)
         if: github.event_name == 'pull_request' && matrix.python-version == '3.13'
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
         with:
           clean: true
 
@@ -91,7 +91,7 @@ jobs:
           echo ${{ github.event.pull_request.base.ref || 'main' }} > ./BASE_BRANCH
 
       - name: Upload Coverage Artifacts
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@v7
         if: github.event_name == 'pull_request' && matrix.python-version == '3.13'
         with:
           name: coverage-data
@@ -109,7 +109,7 @@ jobs:
         run: uv run pytest --cov=a2a --cov-report term --cov-fail-under=88
 
       - name: Upload Artifact (base)
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@v7
         if: github.event_name != 'pull_request' && matrix.python-version == '3.13'
         with:
           name: coverage-report