Don't extend configuration testCompile from shaded

* using testCompile has been discouraged since Gradle 3.4
* made sure dependencies on all other configurations are unchanged
* no need to change it to testImplementation since testCompileClasspath
  and testRuntimeClasspath extend from implementation

gradle/shading.gradle

@@ -4,7 +4,7 @@ apply plugin: 'com.gradleup.shadow'
 
 configurations {
     shaded
-    [apiElements, implementation, compileOnly, testCompile]*.extendsFrom shaded
+    [apiElements, implementation, compileOnly]*.extendsFrom shaded
 }
 configurations.api.canBeResolved = true