chore(deps): bump actions/checkout in /.github/actions/fetch-vectors (#13903)

Bumps [actions/checkout](https://github.com/actions/checkout) from 5.0.1 to 6.0.0.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@93cb6ef...1af3b93)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-version: 6.0.0
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

.github/actions/fetch-vectors/action.yml

@@ -5,15 +5,15 @@ runs:
   using: "composite"
 
   steps:
-    - uses: actions/checkout@93cb6efe18208431cddfb8368fd83d5badbf9bfd # v5.0.1
+    - uses: actions/checkout@1af3b93b6815bc44a9784bd300feb67ff0d1eeb3 # v6.0.0
       with:
         repository: "C2SP/wycheproof"
         path: "wycheproof"
         # Latest commit on the wycheproof main branch, as of Nov 18, 2025.
         ref: "e3c37e9db0f85a762dfcef1642b046bd31090ca4" # wycheproof-ref
         persist-credentials: false
 
-    - uses: actions/checkout@93cb6efe18208431cddfb8368fd83d5badbf9bfd # v5.0.1
+    - uses: actions/checkout@1af3b93b6815bc44a9784bd300feb67ff0d1eeb3 # v6.0.0
       with:
         repository: "C2SP/x509-limbo"
         path: "x509-limbo"