ci: Add bashcov codecov report

.github/workflows/ci.yml

@@ -22,6 +22,23 @@ jobs:
     - name: Test code
       run: test/run
 
+  code-coverage:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - uses: actions/setup-ruby@v1
+        with:
+          ruby-version: '2.7'
+    - name: Install Ruby dependencies
+      run: bundle update --bundler && bundle install
+    - name: Run tests
+      run: bashcov test/run
+    - name: Upload reports to Codecov
+      run: |
+        curl -Os https://uploader.codecov.io/latest/linux/codecov
+        chmod +x codecov
+        ./codecov -f coverage/codecov-result.json -Z
+
   build-docs:
     runs-on: ubuntu-latest