Bump actions/checkout from 5 to 6 (#877)

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/build_docs.yaml

@@ -16,7 +16,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           persist-credentials: false
 

.github/workflows/release.yaml

@@ -17,7 +17,7 @@ jobs:
     name: Build
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: actions/setup-python@v6
         with:
           python-version: '3.12'

.github/workflows/tests.yaml

@@ -20,7 +20,7 @@ jobs:
   linting:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: actions/setup-python@v6
         with:
           python-version: '3.12'
@@ -51,7 +51,7 @@ jobs:
             run-with-scipy: 'NO'
             gdal-version: '3.9.3'
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       - name: Update
         run: |
@@ -112,7 +112,7 @@ jobs:
         run-with-scipy: ['YES']
 
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       - name: Setup Conda
         uses: mamba-org/setup-micromamba@v2
@@ -178,7 +178,7 @@ jobs:
     name: Test latest dependencies
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       - name: Setup Conda
         uses: mamba-org/setup-micromamba@v2