build(deps): bump actions/checkout from 6 to 7 (#29)

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

Author: dependabot[bot]

.github/workflows/ci.yml

@@ -20,7 +20,7 @@ jobs:
     steps:
 
     - name: Checkout
-      uses: actions/checkout@v6
+      uses: actions/checkout@v7
 
     - name: Setup Python
       uses: actions/setup-python@v6
@@ -106,7 +106,7 @@ jobs:
         egress-policy: audit
 
     - name: Checkout
-      uses: actions/checkout@v6
+      uses: actions/checkout@v7
 
     - name: Setup MPI
       id:   setup-mpi
@@ -190,7 +190,7 @@ jobs:
         egress-policy: audit
 
     - name: Checkout
-      uses: actions/checkout@v6
+      uses: actions/checkout@v7
 
     - name: Setup MPICH
       id:   setup1
@@ -232,7 +232,7 @@ jobs:
         egress-policy: audit
 
     - name: Checkout
-      uses: actions/checkout@v6
+      uses: actions/checkout@v7
 
     - name: Setup MPICH
       id:   setup1
@@ -267,7 +267,7 @@ jobs:
         egress-policy: audit
 
     - name: Checkout
-      uses: actions/checkout@v6
+      uses: actions/checkout@v7
 
     - name: Setup MPICH
       id:   setup1
@@ -313,7 +313,7 @@ jobs:
         egress-policy: audit
 
     - name: Checkout
-      uses: actions/checkout@v6
+      uses: actions/checkout@v7
 
     - name: Setup Intel MPI
       id:   setup1