update readme version to 100.3, add link to toolkit repo
# ArcGIS Runtime Java SDK Samples
-### 100.2.1
+### 100.3.0
This project includes a set of samples demonstrating how to accomplish various mapping and GIS tasks with the ArcGIS Runtime SDK for Java.
+Be sure to also check out our [toolkit on GitHub](https://github.com/Esri/arcgis-runtime-toolkit-java).
+
These samples are built with Gradle. If you want to learn more about Gradle, learn more from [Gradle's guide](https://docs.gradle.org/current/userguide/userguide.html).
This guide has instructions for running samples using the command line or with Eclipse and IntelliJ IDEA.
