Merge pull request #374 from pinges/updateAntlr4

Update antlr4 version (Issue 373)
diff --git a/dependency-versions.gradle b/dependency-versions.gradle
index 66d6b87..9d31c05 100644
--- a/dependency-versions.gradle
+++ b/dependency-versions.gradle
@@ -70,7 +70,7 @@
 
     dependency('javax.servlet:javax.servlet-api:4.0.1')
     dependency('javax.persistence:javax.persistence-api:2.2')
-    dependencySet(group: 'org.antlr', version: '4.7.1') {
+    dependencySet(group: 'org.antlr', version: '4.9.3') {
       entry 'antlr4'
       entry 'antlr4-runtime'
     }