fix the badge link (#421)

README.md

@@ -1,6 +1,6 @@
 # Easegress
 
-[![Go Report Card](https://goreportcard.com/badge/github.com/megaease/easegress)](https://goreportcard.com/report/github.com/megaease/easegress) [![GitHub Workflow Status (branch)](https://img.shields.io/github/workflow/status/megaease/easegress/Test/main)](https://github.com/haoel/easegress/actions/workflows/test.yml) [![codecov](https://codecov.io/gh/megaease/easegress/branch/main/graph/badge.svg?token=5Q80B98LPI)](https://codecov.io/gh/megaease/easegress) [![License](https://img.shields.io/badge/License-Apache%202.0-blue.svg)](https://opensource.org/licenses/Apache-2.0) [![GitHub go.mod Go version](https://img.shields.io/github/go-mod/go-version/megaease/easegress)](https://github.com/haoel/easegress/blob/main/go.mod) [![Join MegaEase Slack](https://img.shields.io/badge/slack-megaease-brightgreen?logo=slack)](https://join.slack.com/t/openmegaease/shared_invite/zt-upo7v306-lYPHvVwKnvwlqR0Zl2vveA) 
+[![Go Report Card](https://goreportcard.com/badge/github.com/megaease/easegress)](https://goreportcard.com/report/github.com/megaease/easegress) [![GitHub Workflow Status (branch)](https://img.shields.io/github/workflow/status/megaease/easegress/Test/main)](https://github.com/megaease/easegress/actions/workflows/test.yml) [![codecov](https://codecov.io/gh/megaease/easegress/branch/main/graph/badge.svg?token=5Q80B98LPI)](https://codecov.io/gh/megaease/easegress) [![License](https://img.shields.io/badge/License-Apache%202.0-blue.svg)](https://opensource.org/licenses/Apache-2.0) [![GitHub go.mod Go version](https://img.shields.io/github/go-mod/go-version/megaease/easegress)](https://github.com/megaease/easegress/blob/main/go.mod) [![Join MegaEase Slack](https://img.shields.io/badge/slack-megaease-brightgreen?logo=slack)](https://join.slack.com/t/openmegaease/shared_invite/zt-upo7v306-lYPHvVwKnvwlqR0Zl2vveA) 
 
 <a href="https://megaease.com/easegress">
  <img src="./doc/imgs/easegress.svg"