Bump actions/checkout from 3.5.0 to 4.1.1 (#945)

Bumps [actions/checkout](https://github.com/actions/checkout) from 3.5.0 to 4.1.1.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@8f4b7f8...b4ffde6)

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

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

.github/workflows/build.yaml

@@ -30,7 +30,7 @@ jobs:
         - "samples/admob/rewarded_example"
         - "samples/admob/rewarded_interstitial_example"   
     steps:
-      - uses: actions/checkout@8f4b7f84864484a7bf31766abe9204da3cbe65b3
+      - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11
         with:
           fetch-depth: 0
       - name: "Install Flutter"
@@ -62,7 +62,7 @@ jobs:
         - "samples/admob/rewarded_example"
         - "samples/admob/rewarded_interstitial_example" 
     steps:
-      - uses: actions/checkout@8f4b7f84864484a7bf31766abe9204da3cbe65b3
+      - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11
         with:
           fetch-depth: 0  
       - name: "Install Flutter"
@@ -95,7 +95,7 @@ jobs:
         - "samples/admob/rewarded_example"
         - "samples/admob/rewarded_interstitial_example" 
     steps:
-      - uses: actions/checkout@8f4b7f84864484a7bf31766abe9204da3cbe65b3
+      - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11
         with:
           fetch-depth: 0
       - name: "Install Flutter"

.github/workflows/google_mobile_ads.yaml

@@ -34,7 +34,7 @@ jobs:
     if: github.event_name == 'pull_request'
     timeout-minutes: 30
     steps:
-      - uses: actions/checkout@8f4b7f84864484a7bf31766abe9204da3cbe65b3
+      - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11
         with:
           fetch-depth: 0
       - uses: actions/setup-java@v4
@@ -56,7 +56,7 @@ jobs:
     runs-on: macos-latest
     timeout-minutes: 40
     steps:
-      - uses: actions/checkout@8f4b7f84864484a7bf31766abe9204da3cbe65b3
+      - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11
         with:
           fetch-depth: 0
       - name: "Install Flutter"
@@ -83,7 +83,7 @@ jobs:
     if: github.event_name == 'pull_request'
     timeout-minutes: 30
     steps:
-      - uses: actions/checkout@8f4b7f84864484a7bf31766abe9204da3cbe65b3
+      - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11
         with:
           fetch-depth: 0
       - name: "Install Flutter"