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/build-on-msys2.yml

@@ -24,7 +24,7 @@ jobs:
       Configuration: ${{ matrix.configuration }}
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v6
+        uses: actions/checkout@v7
         with:
           submodules: true
 

.github/workflows/build-sakura.yml

@@ -43,7 +43,7 @@ jobs:
     # Steps represent a sequence of tasks that will be executed as part of the job
     steps:
     ## see https://github.com/actions/checkout
-    - uses: actions/checkout@v6
+    - uses: actions/checkout@v7
       with:
         fetch-depth: 0
         submodules: true
@@ -156,7 +156,7 @@ jobs:
       BUILD_CONFIGURATION: Debug
 
     steps:
-    - uses: actions/checkout@v6
+    - uses: actions/checkout@v7
       with:
         fetch-depth: 0
         submodules: true

.github/workflows/check-encoding.yml

@@ -18,7 +18,7 @@ jobs:
     runs-on: windows-latest
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v6
+        uses: actions/checkout@v7
         with:
           fetch-depth: 0  # 過去の履歴も含めて全て取得 (checkEncoding.py で origin/master にアクセスするため)
 

.github/workflows/cppcheck.yml

@@ -25,7 +25,7 @@ jobs:
       Configuration: ${{ matrix.Configuration }}
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v6
+        uses: actions/checkout@v7
 
       - name: Set up MSYS2
         uses: msys2/setup-msys2@v2

.github/workflows/doxygen.yml

@@ -25,7 +25,7 @@ jobs:
       Configuration: ${{ matrix.Configuration }}
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v6
+        uses: actions/checkout@v7
 
       - name: Set up MSYS2
         uses: msys2/setup-msys2@v2

.github/workflows/python-check.yml

@@ -21,7 +21,7 @@ jobs:
         python-version: ['3.x']
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v6
+        uses: actions/checkout@v7
 
       - name: Set up Python ${{ matrix.python-version }}
         uses: actions/setup-python@v6

.github/workflows/sonarscan.yml

@@ -13,7 +13,7 @@ jobs:
 
     steps:
     - name: Checkout
-      uses: actions/checkout@v6
+      uses: actions/checkout@v7
       with:
         ref: ${{ github.event.workflow_run.head_sha }}
         fetch-depth: 0