Bump actions/checkout from 5 to 6 (#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>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

.github/workflows/check-for-new-releases.yml

@@ -19,7 +19,7 @@ jobs:
     runs-on: windows-2022
 
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           persist-credentials: false
 

.github/workflows/codeql-analysis.yml

@@ -19,7 +19,7 @@ jobs:
     runs-on: ubuntu-24.04
 
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           persist-credentials: false
 

.github/workflows/main.yml

@@ -22,7 +22,7 @@ jobs:
         architecture: [ x64, arm64 ]
 
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           persist-credentials: false
 
@@ -61,7 +61,7 @@ jobs:
         architecture: [ x64 ]
 
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           persist-credentials: false
 
@@ -94,7 +94,7 @@ jobs:
     runs-on: macos-15-intel
 
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           persist-credentials: false
 
@@ -126,7 +126,7 @@ jobs:
     runs-on: macos-14
 
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           persist-credentials: false
 
@@ -165,7 +165,7 @@ jobs:
         architecture: [ x86 ]
 
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           persist-credentials: false
 
@@ -215,7 +215,7 @@ jobs:
       ARTIFACT_NAME: windows-${{matrix.architecture}}-${{matrix.buildType}}-${{matrix.openmp}}${{matrix.all == true && '-all' || ''}}${{matrix.linkRuntime == true && '-linked-runtime' || ''}}
 
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           persist-credentials: false
 
@@ -272,7 +272,7 @@ jobs:
       contents: write
 
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       - uses: actions/download-artifact@v6
         name: Download artifacts