chore: upgrade actions/checkout to v4

.github/workflows/rust.yml

@@ -2,27 +2,26 @@ name: Rust
 
 on:
   push:
-    branches: [ "main" ]
+    branches: ["main"]
   pull_request:
-    branches: [ "main" ]
+    branches: ["main"]
 
 env:
   CARGO_TERM_COLOR: always
 
 jobs:
   build:
-
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v3
-    - name: Run clippy
-      run: cargo clippy --verbose
-    - name: Check formatting
-      run: cargo fmt --check --verbose
-    - name: Run tests
-      run: cargo test --verbose
-    - name: Build
-      run: cargo build --verbose
-    - name: Generate documentation
-      run: cargo doc --verbose
+      - uses: actions/checkout@v4
+      - name: Run clippy
+        run: cargo clippy --verbose
+      - name: Check formatting
+        run: cargo fmt --check --verbose
+      - name: Run tests
+        run: cargo test --verbose
+      - name: Build
+        run: cargo build --verbose
+      - name: Generate documentation
+        run: cargo doc --verbose