added codecov.yml

Author: asmyasnikov

codecov.yml

@@ -0,0 +1,8 @@
+# https://github.com/codecov/support/blob/master/codecov.yml
+# 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.
+#
+ignore:
+  - trace
+  - testutil