[pom] Fix generator jar

pom.xml

@@ -123,7 +123,7 @@
       <!-- Generators -->
       <dependency>
         <groupId>org.mybatis.generator</groupId>
-        <artifactId>mybatis-generator</artifactId>
+        <artifactId>mybatis-generator-core</artifactId>
         <version>1.4.2</version>
       </dependency>
       <dependency>