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] <[email protected]>

Author: dependabot[bot]

.github/workflows/benchmarks.yml

@@ -17,7 +17,7 @@ jobs:
     steps:
       # We need the full repo to avoid this issue
       # https://github.com/actions/checkout/issues/23
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           fetch-depth: 0
 

.github/workflows/ci-additional.yaml

@@ -22,7 +22,7 @@ jobs:
     outputs:
       triggered: ${{ steps.detect-trigger.outputs.trigger-found }}
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           fetch-depth: 2
       - uses: xarray-contrib/[email protected]
@@ -39,7 +39,7 @@ jobs:
       PYTHON_VERSION: "3.13"
 
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           fetch-depth: 0 # Fetch all history for all branches and tags.
 
@@ -80,7 +80,7 @@ jobs:
       PYTHON_VERSION: "3.13"
 
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           fetch-depth: 0 # Fetch all history for all branches and tags.
 

.github/workflows/ci.yaml

@@ -38,7 +38,7 @@ jobs:
             env: "numpy1"
             python-version: "3.11"
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           fetch-depth: 0 # Fetch all history for all branches and tags.
       - name: Set environment variables
@@ -94,7 +94,7 @@ jobs:
     name: xarray-groupby
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           repository: "pydata/xarray"
           fetch-depth: 0 # Fetch all history for all branches and tags.

.github/workflows/pypi.yaml

@@ -11,7 +11,7 @@ jobs:
       contents: read
       id-token: write
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - name: Set up Python and uv
         uses: astral-sh/setup-uv@v7
         with:

.github/workflows/testpypi-release.yaml

@@ -17,7 +17,7 @@ jobs:
     if: ${{ contains( github.event.pull_request.labels.*.name, 'test-build') && github.event_name == 'pull_request' || github.event_name == 'workflow_dispatch' }}
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           fetch-depth: 0
 
@@ -56,7 +56,7 @@ jobs:
       id-token: write
     steps:
       # need pyproject.toml for uv publish --index testpypi
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           fetch-depth: 0 # Fetch all history for all branches and tags.
 

.github/workflows/upstream-dev-ci.yaml

@@ -33,7 +33,7 @@ jobs:
       matrix:
         python-version: ["3.13"]
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           fetch-depth: 0 # Fetch all history for all branches and tags.
       - name: Set environment variables