add codecov.yml to lower threshold

.codecov.yml

@@ -0,0 +1,24 @@
+
+#
+# This codecov.yml is the default configuration for
+# all repositories on Codecov. You may adjust the settings
+# below in your own codecov.yml in your repository.
+#
+coverage:
+  precision: 2
+  round: down
+  range: 70...100
+
+  status:
+    # Learn more at https://codecov.io/docs#yaml_default_commit_status
+    project: 
+      default:
+        threshold: 1% # allow this much decrease on project
+    patch: 
+      default:
+        threshold: 50% # allow this much decrease on patch
+    changes: false
+
+comment:
+  layout: "header, diff"
+  behavior: default  # update if exists else create new