Bump actions/checkout from 5 to 6 (#186)

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-tests.yaml

@@ -16,7 +16,7 @@ jobs:
     permissions:
       security-events: write
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: github/codeql-action/init@v4
         with:
           config-file: .github/codeql/config.yml
@@ -31,7 +31,7 @@ jobs:
     env:
       TOXENV: ${{ matrix.step }}
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: actions/setup-python@v6
         with:
           python-version: "3.13"
@@ -63,7 +63,7 @@ jobs:
       POSTGRES_HOST: 127.0.0.1
       TOXENV: ${{ format('py{0}-unit', matrix.python) }}
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: actions/setup-python@v6
         with:
           python-version: ${{ matrix.python }}
@@ -111,7 +111,7 @@ jobs:
     needs: [ "unit-tests" ]
     runs-on: ubuntu-24.04
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - name: "Download artifacts"
         uses: actions/download-artifact@v6
       - name: "Upload coverage to Codecov"

.github/workflows/release.yml

@@ -15,7 +15,7 @@ jobs:
       contents: write
     if: ${{ github.event.workflow_run.conclusion == 'success' }}
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - name: "Get version"
         run: echo "PLUGIN_VERSION=$(cat streamflow/plugins/unito/postgresql/version.py | grep -oP '(?<=VERSION = \")(.*)(?=\")')" >> $GITHUB_ENV
       - name: "Check tag existence"
@@ -44,7 +44,7 @@ jobs:
       id-token: write
     if: ${{ github.event.workflow_run.conclusion == 'success' }}
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: actions/setup-python@v6
         with:
           python-version: "3.13"