ci: bump actions/checkout from 5 to 6 (#3900)

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

Author: dependabot[bot]

.github/workflows/benchmark.yml

@@ -25,7 +25,7 @@ jobs:
       ASV_DIR: "./benchmarks"
 
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with: { fetch-depth: 0 } # no blob:none so ASV can compare commits
 
       - name: Fetch main branch for `asv run`’s hash

.github/workflows/check-pr.yml

@@ -53,7 +53,7 @@ jobs:
     needs: check-milestone
     if: github.event.pull_request.user.login != 'pre-commit-ci[bot]' && needs.check-milestone.outputs.no-relnotes-reason == '' && !contains(fromJSON('["style","refactor","test","build","ci"]'), needs.check-milestone.outputs.type)
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with: { filter: 'blob:none', fetch-depth: 0 }
       - name: Find out if a relevant release fragment is added
         uses: dorny/paths-filter@v3

.github/workflows/ci.yml

@@ -21,7 +21,7 @@ jobs:
     outputs:
       envs: ${{ steps.get-envs.outputs.envs }}
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with: { filter: 'blob:none', fetch-depth: 0 }
       - uses: astral-sh/setup-uv@v7
         with: { enable-cache: false }
@@ -45,7 +45,7 @@ jobs:
       matrix:
         env: ${{ fromJSON(needs.get-environments.outputs.envs) }}
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with: { filter: 'blob:none', fetch-depth: 0 }
 
       - uses: astral-sh/setup-uv@v7
@@ -101,7 +101,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with: { filter: 'blob:none', fetch-depth: 0 }
       - uses: actions/setup-python@v6
         with:

.github/workflows/publish.yml

@@ -14,7 +14,7 @@ jobs:
     permissions:
       id-token: write # to authenticate as Trusted Publisher to pypi.org
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with: { filter: 'blob:none', fetch-depth: 0 }
       - uses: actions/setup-python@v6
         with: