codecov.yml: override codecov.io defaults

The default values tends to mark most PRs as red, which is annoying.

Author: maruel

codecov.yml

@@ -0,0 +1,20 @@
+# Copyright 2020 The Periph Authors. All rights reserved.
+# Use of this source code is governed under the Apache License, Version 2.0
+# that can be found in the LICENSE file.
+
+# https://docs.codecov.io/docs/codecovyml-reference
+# and
+# https://docs.codecov.io/docs/coverage-configuration
+coverage:
+  precision: 1
+  range: "40...80"
+  round: nearest
+  status:
+    patch:
+      default:
+        target: 60%
+        threshold: 10%
+    project:
+      default:
+        target: 60%
+        threshold: 10%