ci: Ignore demo folder

Coverage for the demo folder is not relevant... can be ignored
diff --git a/codecov.yml b/codecov.yml
index 217b52c..7af2399 100644
--- a/codecov.yml
+++ b/codecov.yml
@@ -11,3 +11,6 @@
 comment:
   layout: "diff, files"
   require_changes: true
+  
+ ignore:
+  - "erpnext/demo"