Bump actions/checkout from 5 to 6 (#747)

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

Author: dependabot[bot]

.github/workflows/CompatHelper.yml

@@ -9,7 +9,7 @@ jobs:
   CompatHelper:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - name: Get Julia compatibility
         id: julia_compat
         # NOTE: this requires a Julia compat lower-bound with minor version!

.github/workflows/Format.yml

@@ -16,7 +16,7 @@ jobs:
     if: github.event.pull_request.draft == false
     steps:
       - name: Check out repository
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
         with:
           ref: ${{github.event.pull_request.head.ref}}
           repository: ${{github.event.pull_request.head.repo.full_name}}

.github/workflows/Test.yml

@@ -79,7 +79,7 @@ jobs:
             arch: 'x64'
             llvm_args: '--opaque-pointers'
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       - name: Install Julia
         uses: julia-actions/setup-julia@v2
@@ -127,7 +127,7 @@ jobs:
           #  build: 'x86_64-linux-gnuassert'
           #  branch: 'master'
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       - name: Download Julia
         env: