[2.19] Change com.github.johnrengelman.shadow to com.gradleup.shadow

Signed-off-by: Craig Perkins <cwperx@amazon.com>

Author: cwperks

spi/build.gradle

@@ -7,7 +7,7 @@ import com.github.jengelman.gradle.plugins.shadow.ShadowBasePlugin
 import org.opensearch.gradle.test.RestIntegTestTask
 
 plugins {
-    id 'com.github.johnrengelman.shadow'
+    id 'com.gradleup.shadow'
     id 'jacoco'
     id 'maven-publish'
     id 'signing'