Bump actions/checkout from 6 to 7 (#1600)

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>
Co-authored-by: Ryan Shepherd <ryansh@microsoft.com>

Author: dependabot[bot]

.github/workflows/check-line-endings.yml

@@ -11,7 +11,7 @@ jobs:
     name: Enforce .gitattributes line endings
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v7
 
       - name: Check for line ending violations
         run: |

.github/workflows/ci.yml

@@ -26,7 +26,7 @@ jobs:
             config: Release
     runs-on: ${{ matrix.toolchain.image }}
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v7
 
       - name: Download nuget
         run: |
@@ -113,7 +113,7 @@ jobs:
             test_exe: test_cpp20_module
     runs-on: ${{ matrix.toolchain.image }}
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v7
 
       - name: Fetch cppwinrt executables
         if: matrix.arch != 'arm64'
@@ -263,7 +263,7 @@ jobs:
       CMAKE_COLOR_DIAGNOSTICS: 1
       CLICOLOR_FORCE: 1
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v7
 
       - name: Install cross compiler
         run: |
@@ -296,7 +296,7 @@ jobs:
         Deployment: [Component, Standalone]
     runs-on: windows-2025-vs2026
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v7
 
       - name: Download nuget
         run: |
@@ -339,7 +339,7 @@ jobs:
             platform_toolset: v145
     runs-on: ${{ matrix.toolchain.image }}
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v7
 
       - name: Fetch cppwinrt executables
         uses: actions/download-artifact@v8
@@ -384,7 +384,7 @@ jobs:
     name: Build nuget package with MSVC
     runs-on: windows-2025-vs2026
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v7
 
       - name: Package
         run: |