Bump org.codehaus.mojo:exec-maven-plugin from 3.3.0 to 3.4.0 (#585)

pom.xml

@@ -93,7 +93,7 @@
 
     <build-helper-maven-plugin.version>3.6.0</build-helper-maven-plugin.version>
     <buildnumber-maven-plugin.version>3.2.0</buildnumber-maven-plugin.version>
-    <exec-maven-plugin.version>3.3.0</exec-maven-plugin.version>
+    <exec-maven-plugin.version>3.4.0</exec-maven-plugin.version>
     <hamcrest.version>3.0</hamcrest.version>
     <hpi-plugin.version>3.56</hpi-plugin.version>
     <incrementals-enforce-minimum.version>1.0-beta-4</incrementals-enforce-minimum.version>