chore(deps): bump actions/checkout from 5 to 6 in the actions group

Bumps the actions group with 1 update: [actions/checkout](https://github.com/actions/checkout).


Updates `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
  dependency-group: actions
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

.github/workflows/ci.yml

@@ -15,11 +15,11 @@ jobs:
     # Change to warp-ubuntu-latest-x64-16x for a more powerful runner (GitHub App must be enabled for this repo)
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           repository: argumentcomputer/ci-workflows
       - uses: ./.github/actions/ci-env
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: dtolnay/rust-toolchain@stable
       - uses: taiki-e/install-action@nextest
       - uses: Swatinem/rust-cache@v2
@@ -30,11 +30,11 @@ jobs:
   lints:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           repository: argumentcomputer/ci-workflows
       - uses: ./.github/actions/ci-env
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: dtolnay/rust-toolchain@stable
       - uses: Swatinem/rust-cache@v2
       - name: Check Rustfmt code style