chore: update actions/checkout and replace unmaintained actions-rs/cargo (#138)

.github/workflows/ci.yml

@@ -12,7 +12,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Build
       run: cargo build --verbose
     - name: Build with OTel feature
@@ -22,7 +22,4 @@ jobs:
     - name: Run tests with OTel feature
       run: cargo test --verbose --features otel
     - name: rustfmt
-      uses: actions-rs/cargo@v1
-      with:
-        command: fmt
-        args: --all -- --check
+      run: cargo fmt --all --check