#19 Maven plugin url incorrect in Readme.md (#20)

Author: valinha

README.md

@@ -8,7 +8,7 @@
 
 Please refer to:
 * Gradle plugin: [graphql-java-codegen-gradle-plugin](https://github.com/kobylynskyi/graphql-java-codegen-gradle-plugin)
-* Maven plugin: [grapqhl-java-codegen-maven-plugin](https://github.com/kobylynskyi/grapqhl-java-codegen-maven-plugin) 
+* Maven plugin: [grapqhl-java-codegen-maven-plugin](https://github.com/kobylynskyi/graphql-java-codegen-maven-plugin) 
 
 
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