Add codecov to actions

Author: james-w

.github/workflows/cargo.yml

@@ -31,13 +31,19 @@ jobs:
     - name: Run cargo fmt
       run: cargo fmt --check
     - name: Run tests
-      run: cargo llvm-cov --all-features --workspace --codecov --output-path lcov.info nextest
+      run: cargo llvm-cov --all-features --workspace --codecov --output-path codecov.json nextest
     - name: Show coverage report
       run: cargo llvm-cov report
     - name: Check link
       uses: actions-rs/clippy-check@v1
       with:
         token: ${{ secrets.GITHUB_TOKEN }}
         args: --all-targets --all-features -- -D warnings
+    - name: Upload coverage to Codecov
+      uses: codecov/codecov-action@v3
+      with:
+        token: ${{ secrets.CODECOV_TOKEN }} # not required for public repos
+        files: codecov.json
+        fail_ci_if_error: true
     - name: Run cargo check
       run: cargo check