Adjust shadowJar name. (#909)

Signed-off-by: Thomas Hurney <hurneyt@amazon.com>

Author: AWSHurneyt

build.gradle

@@ -58,7 +58,7 @@ apply plugin: 'java'
 apply plugin: 'jacoco'
 apply plugin: 'signing'
 apply plugin: 'maven-publish'
-apply plugin: 'com.github.johnrengelman.shadow'
+apply plugin: 'com.gradleup.shadow'
 // apply plugin: 'io.gitlab.arturbosch.detekt'
 apply plugin: 'org.jetbrains.kotlin.jvm'
 apply plugin: 'org.jetbrains.kotlin.plugin.allopen'