Update documentation about prior releases

Author: rjeberhard

documentation/site/content/_index.md

@@ -43,7 +43,7 @@ See the [Release Notes](https://github.com/oracle/weblogic-kubernetes-operator/r
 
 #### Operator earlier versions
 
-Documentation for supported prior releases of the operator: [3.4](https://oracle.github.io/weblogic-kubernetes-operator/3.4/) and [4.0](https://oracle.github.io/weblogic-kubernetes-operator/4.0/).
+Documentation for supported prior releases of the operator: [3.4](https://oracle.github.io/weblogic-kubernetes-operator/3.4/), [4.0](https://oracle.github.io/weblogic-kubernetes-operator/4.0/), and [4.1](https://oracle.github.io/weblogic-kubernetes-operator/4.1/).
 
 #### Backward compatibility guidelines