Update README.md

Fix gradle plugin badge

Author: kobylynskyi

plugins/gradle/README.md

@@ -1,7 +1,7 @@
 # GraphQL Codegen Gradle plugin #
 
 ![Build](https://github.com/kobylynskyi/graphql-java-codegen/workflows/Build/badge.svg)
-[![Gradle Plugins](https://img.shields.io/maven-metadata/v/https/plugins.gradle.org/m2/io/github/kobylynskyi/graphql-codegen-gradle-plugin/maven-metadata.xml.svg?label=gradle)](https://plugins.gradle.org/plugin/io.github.kobylynskyi.graphql.codegen)
+[![Gradle Plugins](https://img.shields.io/maven-metadata/v/https/plugins.gradle.org/m2/io/github/kobylynskyi/graphql-java-codegen-gradle-plugin/maven-metadata.xml.svg?label=gradle)](https://plugins.gradle.org/plugin/io.github.kobylynskyi.graphql.codegen)
 [![License: MIT](https://img.shields.io/badge/License-MIT-yellow.svg)](https://opensource.org/licenses/MIT)
 
 This document describes the gradle plugin for graphql-java-codegen.