build: (deps): bump actions/checkout from 2 to 4

Bumps [actions/checkout](https://github.com/actions/checkout) from 2 to 4.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](https://github.com/actions/checkout/compare/v2...v4)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

.github/workflows/integrate.yaml

@@ -8,7 +8,7 @@ jobs:
   code_tests:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - run: cat .github/workflows/versions.env >> $GITHUB_ENV
       - uses: subosito/flutter-action@v2
         with:
@@ -30,7 +30,7 @@ jobs:
   build_debug_apk:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - run: cat .github/workflows/versions.env >> $GITHUB_ENV
       - uses: actions/setup-java@v1
         with:
@@ -45,7 +45,7 @@ jobs:
   build_debug_web:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - run: cat .github/workflows/versions.env >> $GITHUB_ENV
       - uses: subosito/flutter-action@v2
         with:
@@ -59,7 +59,7 @@ jobs:
   build_debug_linux:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - run: cat .github/workflows/versions.env >> $GITHUB_ENV
       - uses: subosito/flutter-action@v2
         with:
@@ -73,7 +73,7 @@ jobs:
   build_debug_ios:
     runs-on: macos-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - run: cat .github/workflows/versions.env >> $GITHUB_ENV
       - uses: subosito/flutter-action@v2
         with: