fixed error

pom.xml

@@ -51,6 +51,12 @@
   </properties>
 
   <dependencies>
+    <dependency>
+      <groupId>org.antlr</groupId>
+      <artifactId>antlr4-runtime</artifactId>
+      <version>4.7.1</version>
+    </dependency>
+
     <dependency>
       <groupId>de.monticore.lang</groupId>
       <artifactId>Tagging</artifactId>