Bump min required Maven version to 3.1.1

Author: slachiewicz

modello-maven-plugin/pom.xml

@@ -22,7 +22,7 @@
 
   <properties>
     <mavenPluginTools>3.6.1</mavenPluginTools>
-    <maven.version>3.1.0</maven.version>
+    <maven.version>3.1.1</maven.version>
   </properties>
 
   <dependencies>