Bump actions/checkout from 4 to 6

Bumps [actions/checkout](https://github.com/actions/checkout) from 4 to 6.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v4...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>

Author: dependabot[bot]

.github/workflows/ci.yml

@@ -97,7 +97,7 @@ jobs:
         unset CMAKE_VERSION
         unset GIT_VERSION
 
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v6
       with:
         submodules: recursive
         persist-credentials: false
@@ -341,7 +341,7 @@ jobs:
       # Prevent one job from pausing the rest
       fail-fast: false
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v6
       with:
         submodules: recursive
         persist-credentials: false
@@ -422,7 +422,7 @@ jobs:
       # Prevent one job from pausing the rest
       fail-fast: false
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v6
       with:
         submodules: recursive
         persist-credentials: false
@@ -601,7 +601,7 @@ jobs:
             artifact-output: artifact_windows
       fail-fast: false
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v6
       with:
         path: 'cutter-src-tmp'
         persist-credentials: false

.github/workflows/coverity-scan.yml

@@ -7,7 +7,7 @@ jobs:
   latest:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
         with:
           submodules: recursive
       - uses: actions/setup-python@v5

.github/workflows/docs.yml

@@ -9,7 +9,7 @@ jobs:
   deploy:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
         with:
           submodules: recursive
       - name: install dependencies

.github/workflows/linter.yml

@@ -16,7 +16,7 @@ jobs:
     outputs:
       clang-format: ${{ steps.filter.outputs.clang-format }}
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v6
     - uses: dorny/paths-filter@v2
       id: filter
       with:
@@ -35,7 +35,7 @@ jobs:
     if: ${{ needs.changes.outputs.clang-format == 'true' }}
     steps:
     - name: Checkout repository
-      uses: actions/checkout@v4
+      uses: actions/checkout@v6
 
     - name: Install wget, software-properties-common, lsb-release (dependencies of LLVM install script)
       run: sudo apt --assume-yes install wget software-properties-common lsb-release