Minor CONTRIBUTING.adoc edits

Signed-off-by: Gopal S Akshintala <[email protected]>

Author: overfullstack

CONTRIBUTING.adoc

@@ -29,7 +29,12 @@ It needs JDK 11 installed in your system.
 Recommendation is to do it via https://sdkman.io/install[SDKMAN].
 After you install SDKMAN,
 run `sdk list java` -> Pick Identifier for your favorite java distribution -> Run `sdk install java <Identifier-you-picked>`
-to install Java.
+to install Java. For example:
+
+[source,bash]
+----
+sdk install java 11.0.22-tem
+----
 
 === Build with Gradle