ci: upload coverage report to codecov

Author: MunifTanjim

.codecov.yml

@@ -0,0 +1,10 @@
+coverage:
+  status:
+    project:
+      default:
+        informational: true
+        only_pulls: true
+    patch:
+      default:
+        informational: true
+        only_pulls: true

.github/workflows/ci.yml

@@ -67,3 +67,6 @@ jobs:
         run: |
             export PATH="${PWD}/build/:${PATH}"
             ./scripts/test.sh
+
+      - name: Upload coverage to Codecov
+        uses: codecov/codecov-action@v2