Update build.gradle

fix build module

Author: alexxxdev

processor-gson/build.gradle

@@ -1,5 +1,6 @@
 apply plugin: 'kotlin'
 apply plugin: "com.github.ben-manes.versions"
+apply plugin: 'maven'
 
 sourceSets {
     main.java.srcDirs += 'src/main/kotlin'
@@ -21,4 +22,4 @@ test {
 }
 
 sourceCompatibility = "7"
-targetCompatibility = "7"
+targetCompatibility = "7"