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/format.yml

@@ -8,7 +8,7 @@ jobs:
   java_format:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: actions/setup-java@v5
         with:
           distribution: 'zulu'
@@ -20,7 +20,7 @@ jobs:
   objc_format:
     runs-on: macos-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - name: Test
         run: |
           which clang-format || brew install clang-format
@@ -32,7 +32,7 @@ jobs:
   swift_format:
     runs-on: macos-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - name: Test
         run: |
           which swiftlint || brew install swiftlint

.github/workflows/validate.yml

@@ -20,7 +20,7 @@ jobs:
     name: Run Dart Analyzer
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: subosito/flutter-action@v2
         with:
           channel: stable
@@ -37,7 +37,7 @@ jobs:
     name: Build Android example app (stable channel)
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: actions/setup-java@v5
         with:
           distribution: 'zulu'
@@ -55,7 +55,7 @@ jobs:
       name: Build Android example app (3.29)
       runs-on: ubuntu-latest
       steps:
-        - uses: actions/checkout@v5
+        - uses: actions/checkout@v6
         - uses: actions/setup-java@v5
           with:
             distribution: 'zulu'
@@ -74,7 +74,7 @@ jobs:
     name: Build iOS example app (stable channel)
     runs-on: macos-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: subosito/flutter-action@v2
         with:
           channel: stable
@@ -88,7 +88,7 @@ jobs:
     name: Build iOS example app (3.29)
     runs-on: macos-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: subosito/flutter-action@v2
         with:
           channel: stable
@@ -103,7 +103,7 @@ jobs:
     name: Build macOS example app (stable channel)
     runs-on: macos-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: subosito/flutter-action@v2
         with:
           channel: stable
@@ -117,7 +117,7 @@ jobs:
     name: Build macOS example app (3.29)
     runs-on: macos-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: subosito/flutter-action@v2
         with:
           channel: stable
@@ -132,7 +132,7 @@ jobs:
     name: Run all unit tests (Dart)
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: subosito/flutter-action@v2
         with:
           channel: stable