build(deps): bump actions/checkout from 5 to 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] <[email protected]>

Author: dependabot[bot]

.github/workflows/build.yaml

@@ -11,7 +11,7 @@ jobs:
 
     steps:
       - name: Checkout code
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: setup-msys2
         uses: msys2/setup-msys2@v2

.github/workflows/cygwin.yml

@@ -18,7 +18,7 @@ jobs:
       HAS_SSH_KEY: ${{ secrets.SSH_KEY != '' }}
 
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
 
     # install build tools
     - name: Install build tools
@@ -105,7 +105,7 @@ jobs:
       run: |
         icacls . /inheritance:r
         icacls . /grant Administrators:F
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
 
     # install cygwin and build tools
     - name: Install Cygwin

.github/workflows/ui-tests.yml

@@ -99,7 +99,7 @@ jobs:
           "$WINDIR/system32/tar.exe" -C "$RUNNER_TEMP" -xvf "$RUNNER_TEMP/win32-openssh.zip" &&
           echo "OPENSSH_FOR_WINDOWS_DIRECTORY=$(cygpath -aw "$RUNNER_TEMP/OpenSSH-Win64")" >>$GITHUB_ENV
 
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           sparse-checkout: |
             ui-tests