chores: remove dead badge

Author: isimluk

README.md

@@ -2,7 +2,6 @@
 ![Build CI](https://github.com/GoComply/xsd2go/workflows/Build%20CI/badge.svg)
 [![Lint CI](https://github.com/GoComply/xsd2go/actions/workflows/lint.yaml/badge.svg)](https://github.com/GoComply/xsd2go/actions/workflows/lint.yaml)
 [![Go Report Card](https://goreportcard.com/badge/github.com/gocomply/xsd2go)](https://goreportcard.com/report/github.com/gocomply/xsd2go)
-[![Gitter](https://badges.gitter.im/GoComply/community.svg)](https://gitter.im/GoComply/community?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge)
 [![PkgGoDev](https://pkg.go.dev/badge/github.com/gocomply/xsd2go)](https://pkg.go.dev/github.com/gocomply/xsd2go)
 
 :warning: **You should run xsd2go, before ever importing `encoding/xml` to your project.** :warning: