ci: add coverage

Author: atsyplenkov

.github/workflows/rust-ci.yml

@@ -65,6 +65,25 @@ jobs:
           RUSTDOCFLAGS: -D warnings
         run: cargo doc --no-deps --document-private-items --all-features --examples
 
+  coverage:
+    name: Coverage
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+      - name: Install Rust toolchain
+        uses: dtolnay/rust-toolchain@stable
+      - name: Install cargo-llvm-cov
+        run: cargo install cargo-llvm-cov
+      - name: Generate coverage report
+        run: cargo llvm-cov --all-targets --lcov --output-path lcov.info
+      - name: Upload to Codecov
+        uses: codecov/codecov-action@v4
+        with:
+          files: lcov.info
+          fail_ci_if_error: true
+          token: ${{ secrets.CODECOV_TOKEN }}
+
   publish-dry-run:
     name: Publish dry run
     runs-on: ubuntu-latest