ci(actions): 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] <support@github.com>

Author: dependabot[bot]

.github/workflows/deno.yml

@@ -13,7 +13,7 @@ jobs:
       - uses: denoland/setup-deno@v2
         with:
           deno-version: v2.x
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       - run: deno lint
       - run: deno fmt --check
@@ -25,7 +25,7 @@ jobs:
       - uses: denoland/setup-deno@v2
         with:
           deno-version: v2.x
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       - run: deno cache *.ts
       - run: deno check *.ts
@@ -37,7 +37,7 @@ jobs:
       - uses: denoland/setup-deno@v2
         with:
           deno-version: v2.x
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       - run: deno cache *.ts
       - run: deno test --no-check  --allow-read