Update latest version number in README.

Author: kishorenc

README.md

@@ -8,15 +8,15 @@ The client is available on Maven central:
 
 ```groovy
 dependencies {
-    implementation 'org.typesense:typesense-java:0.5.0'
+    implementation 'org.typesense:typesense-java:0.8.1'
 }
 ```
 
 ```xml
 <dependency>
     <groupId>org.typesense</groupId>
     <artifactId>typesense-java</artifactId>
-    <version>0.5.0</version>
+    <version>0.8.1</version>
 </dependency>
 ```