Add coverage report to CI

.github/workflows/ci.yml

@@ -62,3 +62,22 @@ jobs:
         with:
           command: clippy
           args: -- -D warnings
+
+  coverage:
+    name: Coverage
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions-rs/toolchain@v1
+        with:
+          profile: minimal
+          toolchain: stable
+          override: true
+      - uses: actions-rs/tarpaulin@v0.1
+      - uses: codecov/codecov-action@v1.0.5
+        with:
+          token: ${{secrets.CODECOV_TOKEN}}
+      - uses: actions/upload-artifact@v1
+        with:
+          name: code-coverage-report
+          path: cobertura.xml