chore: add codecov.yml to make project check informational

The codecov/project check fails on coverage decreases with no config.
Set project status to informational so it reports but doesn't block,
while keeping patch coverage as the gating check.

Author: emjay0921

codecov.yml

@@ -0,0 +1,8 @@
+coverage:
+  status:
+    project:
+      default:
+        informational: true
+    patch:
+      default:
+        target: auto