build(deps): bump actions/checkout from 6 to 7

Bumps [actions/checkout](https://github.com/actions/checkout) from 6 to 7.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v6...v7)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-version: '7'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

.github/workflows/linux.yml

@@ -30,7 +30,7 @@ jobs:
             metis: metis
 
     steps:
-    - uses: actions/checkout@v6
+    - uses: actions/checkout@v7
 
     - name: Update Packages
       run: |

.github/workflows/macos.yml

@@ -27,7 +27,7 @@ jobs:
             metis: metis
 
     steps:
-    - uses: actions/checkout@v6
+    - uses: actions/checkout@v7
 
     - name: Setup Dependencies
       run: >-

.github/workflows/windows.yml

@@ -28,7 +28,7 @@ jobs:
             env: x86_64
 
     steps:
-    - uses: actions/checkout@v6
+    - uses: actions/checkout@v7
 
     - name: Setup Dependencies
       uses: msys2/setup-msys2@v2
@@ -129,7 +129,7 @@ jobs:
             marker: vc18
 
     steps:
-    - uses: actions/checkout@v6
+    - uses: actions/checkout@v7
 
     - name: Cache METIS
       if: matrix.metis == 'metis'