build(deps): 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] <[email protected]>

Author: dependabot[bot]

.github/workflows/main-coverage.yml

@@ -15,7 +15,7 @@ jobs:
     timeout-minutes: 3
     steps:
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Install pnpm
         uses: pnpm/action-setup@v4

.github/workflows/release.yml

@@ -29,7 +29,7 @@ jobs:
     if: github.repository == 'testing-library/eslint-plugin-testing-library'
     steps:
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Install pnpm
         uses: pnpm/action-setup@v4

.github/workflows/smoke-test.yml

@@ -12,7 +12,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Install pnpm
         uses: pnpm/action-setup@v4

.github/workflows/verifications.yml

@@ -14,7 +14,7 @@ jobs:
           ['lint', 'type-check', 'format:check', 'generate-all:check']
     steps:
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Install pnpm
         uses: pnpm/action-setup@v4
@@ -42,7 +42,7 @@ jobs:
         eslint: [8.57.0, 8, 9]
     steps:
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Install pnpm
         uses: pnpm/action-setup@v4