Bump siddhi version

Author: RAVEENSR

pom.xml

@@ -45,7 +45,7 @@
     </profiles>
 
     <properties>
-        <siddhi.version>5.0.2</siddhi.version>
+        <siddhi.version>5.1.1</siddhi.version>
         <siddhi.version.range>[5.0.0,6.0.0)</siddhi.version.range>
         <log4j.version>1.2.17.wso2v1</log4j.version>
         <testng.version>6.11</testng.version>