[BEAM-10986] Rollback to shadow 4.0.3 (#12969)

Author: TheNeuralBit

buildSrc/build.gradle

@@ -37,7 +37,7 @@ repositories {
 dependencies {
   compile gradleApi()
   compile localGroovy()
-  compile 'com.github.jengelman.gradle.plugins:shadow:5.2.0'
+  compile 'com.github.jengelman.gradle.plugins:shadow:4.0.3'
   compile "gradle.plugin.com.github.spotbugs.snom:spotbugs-gradle-plugin:4.5.0"
 
   runtime "net.ltgt.gradle:gradle-apt-plugin:0.21"                                                    // Enable a Java annotation processor