build: change commons-demo scope to test

Author: javier-godoy

pom.xml

@@ -126,6 +126,7 @@
             <groupId>com.flowingcode.vaadin.addons.demo</groupId>
             <artifactId>commons-demo</artifactId>
             <version>${flowingcode.commons.demo.version}</version>
+            <scope>test</scope>
         </dependency>
         <dependency>
             <groupId>org.slf4j</groupId>