Add missing source encoding to wiget-set-testutil

test/widget-set-testutil/pom.xml

@@ -16,6 +16,8 @@
         <maven.compiler.source>1.8</maven.compiler.source>
         <maven.compiler.target>1.8</maven.compiler.target>
         <vaadin.version>${project.version}</vaadin.version>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
     </properties>
 
     <dependencies>