Revert "Dependency(deps): Bump antlr-maven-plugin from 2.1 to 2.2"

This reverts commit f42c98c6c59b8fc6d49b410f0e9cb24c1eb1e256.

jplag.frontend.csharp-1.2/pom.xml

@@ -36,7 +36,7 @@
 			<plugin>
 				<groupId>org.codehaus.mojo</groupId>
 				<artifactId>antlr-maven-plugin</artifactId>
-				<version>2.2</version>
+				<version>2.1</version>
 				<configuration>
 					<!-- Comma separated list of grammar files or pattern grammar files 
 						By default, grammar file(s) is in ${basedir}/src/main/antlr -->