Add a configuration to codecov.io (#636)

* Add a configuration to codecov.io

* Add badge

* Make coverage purely informational

.github/codecov.yml

@@ -0,0 +1,15 @@
+coverage:
+  status:
+    project:
+      default:
+        informational: true
+    patch:
+      default:
+        informational: true
+
+comment:
+  layout: reach, diff, files
+  behavior: default
+  require_base: yes
+  require_head: yes
+  after_n_builds: 5 # Our test matrix currently has 5 configurations

README.md

@@ -4,6 +4,7 @@
 [![Crates.io](https://img.shields.io/crates/v/reedline)](https://crates.io/crates/reedline)
 [![docs.rs](https://img.shields.io/docsrs/reedline)](https://docs.rs/reedline/)
 ![GitHub Workflow Status](https://img.shields.io/github/actions/workflow/status/nushell/reedline/ci.yml?branch=main)
+[![codecov](https://codecov.io/gh/nushell/reedline/graph/badge.svg?token=NUTC465WOL)](https://codecov.io/gh/nushell/reedline)
 [![Discord](https://img.shields.io/discord/601130461678272522.svg?logo=discord)](https://discord.gg/NtAbbGn)
 
 ## Introduction