fix maven publishing

build.gradle

@@ -8,6 +8,7 @@ targetCompatibility = JavaVersion.VERSION_1_8
 
 archivesBaseName = project.archives_base_name
 version = project.mod_version
+group = project.maven_group
 
 minecraft {
 }

gradle.properties

@@ -9,6 +9,7 @@ org.gradle.jvmargs=-Xmx1G
 
 # Mod Properties
     mod_version = 1.0.0
+    maven_group = net.fabricmc
     archives_base_name = fabric-example-mod
 
 # Dependencies