[WSO2-Release] [Release 5.1.11] update documentation for release 5.1.11

Author: wso2-jenkins-bot

README.md

@@ -41,7 +41,7 @@ For more information on using Siddhi refer <a target="_blank" href="https://sidd
 
 ## Latest API Docs 
 
-Latest API Docs is <a target="_blank" href="https://siddhi-io.github.io/siddhi/api/5.1.10">5.1.10</a>.
+Latest API Docs is <a target="_blank" href="https://siddhi-io.github.io/siddhi/api/5.1.11">5.1.11</a>.
 
 ## Support and Contribution