Demo common libs v update (#2298)

* Update version of dependency commons-fileupload
* More details to demo readme

java/demo/README

@@ -14,3 +14,8 @@ How to run the webapp locally?
 
 How to deploy the webapp to Appengine?
   $ mvn gae:update
+
+If you have made any changes to the code or pom.xml file of demo here,
+you may need to run Maven commands like ```mvn clean install -U```
+(especially one hierarchy above i.e at java/ folder) to resolve any
+dependency issues w.r.t new developement version.

java/demo/pom.xml

@@ -78,7 +78,7 @@
     <dependency>
       <groupId>commons-fileupload</groupId>
       <artifactId>commons-fileupload</artifactId>
-      <version>1.2</version>
+      <version>1.3</version>
     </dependency>
     <dependency>
       <groupId>commons-lang</groupId>