Update README

Author: rainboyan

README.md

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+[![Main branch build status](https://github.com/graceframework/grace-doc-engine/workflows/Grace%20CI/badge.svg?style=flat)](https://github.com/graceframework/grace-doc-engine/actions?query=workflow%3A%Grace+CI%22)
+[![Apache 2.0 license](https://img.shields.io/badge/License-APACHE%202.0-green.svg?logo=APACHE&style=flat)](https://opensource.org/licenses/Apache-2.0)
+[![Latest version on Maven Central](https://img.shields.io/maven-central/v/org.graceframework/grace-doc-engine.svg?label=Maven%20Central&logo=apache-maven&style=flat)](https://search.maven.org/search?q=g:org.graceframework)
+[![Grace on X](https://img.shields.io/twitter/follow/graceframework?style=social)](https://x.com/graceframework)
+
+[![Java Version](https://img.shields.io/badge/Java-17-blue?style=flat&logo=openjdk&color=437291)](https://docs.oracle.com/en/java/javase/17/)
+[![Groovy Version](https://img.shields.io/badge/Groovy-4.0.28-blue?logo=apachegroovy&style=flat&color=4298b8)](https://groovy-lang.org/releasenotes/groovy-4.0.html)
+[![Gradle Version](https://img.shields.io/badge/Gradle-7.6.6-blue?logo=gradle&style=flat&color=1da2bd)](https://docs.gradle.org/7.6.6/release-notes.html)
+
+# Grace Doc Engine
+
+This repository is a fork of [Grails GDoc Engine](https://github.com/grails/grails-gdoc-engine/), which has been upgraded to Groovy 4.0, it will be used in Grace Framework](https://github.com/graceframework/grace-framework) 2024.0.
+
+## Versions
+
+- [2.0.x](https://github.com/graceframework/grace-doc-engine)
+- [1.0.x](https://github.com/graceframework/grace-doc-engine/tree/1.0.x)
+
+## Links
+
+- [Grace Framework](https://github.com/graceframework/grace-framework)