CI: Configure thresholds for Codecov

Author: amotl

codecov.yml

@@ -0,0 +1,9 @@
+# https://docs.codecov.io/docs/common-recipe-list
+# https://docs.codecov.io/docs/commit-status#patch-status
+
+coverage:
+  status:
+    project:
+      default:
+        #target: 85%    # the required coverage value
+        threshold: 3%  # the leniency in hitting the target