support codecov

.github/.codecov.yml

@@ -0,0 +1,16 @@
+codecov:
+  notify:
+    wait_for_ci: true
+
+coverage:
+  status:
+    patch:
+      default:
+        threshold: 100% # allow patch coverage to be lower than project coverage by any amount
+    project:
+      default:
+        threshold: 5% # allow project coverage to drop at most 5%
+
+comment: false
+github_checks:
+    annotations: false