Detail which version of JIB to use

- You need to create that property, not update it
- I tested version 2.1.0, we can't know if compatibility will work on newer versions, so we should give a working number here
-------
cc: @KarlErickson

Author: jdubois

articles/container-registry/container-registry-java-quickstart.md

@@ -100,13 +100,13 @@ Finally, you'll update your project configuration and use the command prompt to
 
 1. Navigate to the completed project directory for your Spring Boot application (for example, "*C:\SpringBoot\gs-spring-boot-docker\complete*" or "*/users/robert/SpringBoot/gs-spring-boot-docker/complete*"), and open the *pom.xml* file with a text editor.
 
-1. Update the `<properties>` collection in the *pom.xml* file with the following XML. Replace the placeholder with your registry name, and update the `<jib-maven-plugin.version>` value with the latest version of the [jib-maven-plugin](https://github.com/GoogleContainerTools/jib/tree/master/jib-maven-plugin).
+1. Update the `<properties>` collection in the *pom.xml* file with the following XML. Replace the placeholder with your registry name, and add a `<jib-maven-plugin.version>` property with value `2.1.0`, or a newer version of the [jib-maven-plugin](https://github.com/GoogleContainerTools/jib/tree/master/jib-maven-plugin).
 
    ```xml
    <properties>
       <docker.image.prefix><your registry name>.azurecr.io</docker.image.prefix>
-      <jib-maven-plugin.version>1.8.0</jib-maven-plugin.version>
       <java.version>1.8</java.version>
+      <jib-maven-plugin.version>2.1.0</jib-maven-plugin.version>
    </properties>
    ```