docs(readme): refactor codebase and update dependencies

- Remove Gitter chat badge from README.md

Signed-off-by: appleboy <appleboy.tw@gmail.com>

Author: appleboy

README.md

@@ -4,7 +4,6 @@
 [![codecov](https://codecov.io/gh/gin-contrib/pprof/branch/master/graph/badge.svg)](https://codecov.io/gh/gin-contrib/pprof)
 [![Go Report Card](https://goreportcard.com/badge/github.com/gin-contrib/pprof)](https://goreportcard.com/report/github.com/gin-contrib/pprof)
 [![GoDoc](https://godoc.org/github.com/gin-contrib/pprof?status.svg)](https://godoc.org/github.com/gin-contrib/pprof)
-[![Join the chat at https://gitter.im/gin-gonic/gin](https://badges.gitter.im/Join%20Chat.svg)](https://gitter.im/gin-gonic/gin)
 
 gin pprof middleware