Add code coverage bot

Signed-off-by: Lucas Steuernagel <lucas.tnagel@gmail.com>

.github/workflows/test.yml

@@ -417,3 +417,28 @@ jobs:
           make test
           ./test
         working-directory: ./stdlib
+
+  coverage:
+    runs-on: ubuntu-latest
+    container: ghcr.io/hyperledger/solang-llvm:ci-5
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v3
+        with:
+          submodules: recursive
+      - name: Install Rust
+        uses: dtolnay/rust-toolchain@stable
+        with:
+          components: llvm-tools
+      - name: cargo install cargo-llvm-cov
+        uses: taiki-e/install-action@cargo-llvm-cov
+      - name: cargo llvm-cov
+        run: cargo llvm-cov --all-features --lcov --output-path lcov.info
+        env:
+          CARGO_HUSKY_DONT_INSTALL_HOOKS: true
+      - name: Upload coverage report to codecov.io
+        uses: codecov/codecov-action@v3
+        env:
+          CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}
+        with:
+          fail_ci_if_error: true