optimize: add codecov.yml and badge (alibaba#42)

.licenserc.yaml

@@ -6,6 +6,7 @@ header:
   paths-ignore:
     - '.gitignore'
     - '*.md'
+    - '*.yml'
     - 'LICENSE'
     - '.github/**'
     - '.licenserc.yaml'

README.md

@@ -4,6 +4,9 @@
   Next-generation Cloud Native Gateway
 </h1>
 
+[![Build Status](https://github.com/alibaba/higress/workflows/build%20and%20codecov/badge.svg?branch=main)](https://github.com/alibaba/higress/actions)
+[![license](https://img.shields.io/github/license/alibaba/higress.svg)](https://www.apache.org/licenses/LICENSE-2.0.html)
+
 [**官网**](https://higress.io/) &nbsp; |
 &nbsp; [**文档**](https://higress.io/zh-cn/docs/overview/what-is-higress.html) &nbsp; |
 &nbsp; [**博客**](https://higress.io/zh-cn/blog/index.html) &nbsp; |

codecov.yml

@@ -0,0 +1,20 @@
+codecov:
+  require_ci_to_pass: yes
+coverage:
+  status:
+    patch: no
+    project:
+      default:
+        target: auto
+        threshold: 1%
+        if_not_found: success
+    changes: no
+  precision: 2
+  round: down
+  range: 50..100
+ignore:
+  - "helm/**"
+comment:
+  layout: "reach,diff,flags,tree"
+  behavior: default
+  require_changes: no