Bump actions/checkout from 3 to 4

Bumps [actions/checkout](https://github.com/actions/checkout) from 3 to 4.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v3...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/CI.yml

@@ -10,7 +10,7 @@ jobs:
     steps:
 
     - name: Checkout code
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
 
     - name: Run clippy
       run: cargo fmt -- --check
@@ -22,7 +22,7 @@ jobs:
     steps:
 
     - name: Checkout code
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
 
     - name: Install Rust
       run: |
@@ -43,7 +43,7 @@ jobs:
     steps:
 
     - name: Checkout code
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
 
     - name: Run tests
       run: cargo test
@@ -55,7 +55,7 @@ jobs:
     steps:
 
     - name: Checkout code
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
 
     - name: Install cargo-tarpaulin
       run: |

.github/workflows/release.yml

@@ -28,7 +28,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     steps:
     - name: Check out code
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
 
     - name: Build
       run: cargo build --release
@@ -46,7 +46,7 @@ jobs:
     runs-on: ubuntu-20.04
     steps:
     - name: Check out code
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
 
     - name: Install cross
       run: cargo install cross