Upgrade the shadow dependency and explicitly declare our own dependencies.

I believe that we were previously relying on the shadow plugin to bring in too
many of our dependencies, and with recent versions of the plugin those
dependency declarations went away.

This commit gets the missing dependencies compiling again, and addresses one
backwards incompatible change with the asm-commons library, see:
    https://issues.apache.org/jira/browse/MSHADE-258

jar-plugin/build.gradle

@@ -17,7 +17,14 @@ generateTestConfig {
 
 dependencies {
     compile project(':jruby-gradle-plugin')
-    compile 'com.github.jengelman.gradle.plugins:shadow:[1.2.2,2.0)'  // NEED TO FIX THIS OPEN END
+    /*
+     * NOTE: version 5.0.0 of the shadow plugin supports only Gradle 5.x and later
+     */
+    compile 'com.github.jengelman.gradle.plugins:shadow:[4.0.2,5.0)'
+    compile 'org.codehaus.plexus:plexus-utils:[3.2.0,3.3)'
+    compile 'org.apache.commons:commons-io:1.3.2'
+    compile 'org.ow2.asm:asm-commons:[6.1,6.99)'
+    compile 'org.apache.ant:ant:[1.10.6,2.0)'
 
     testCompile (spockVersion) {
         exclude module : 'groovy-all'

jar-plugin/src/main/groovy/com/github/jrubygradle/jar/internal/JRubyJarCopyAction.groovy

@@ -37,7 +37,7 @@ import org.gradle.internal.UncheckedException
 import org.objectweb.asm.ClassReader
 import org.objectweb.asm.ClassVisitor
 import org.objectweb.asm.ClassWriter
-import org.objectweb.asm.commons.RemappingClassAdapter
+import org.objectweb.asm.commons.ClassRemapper
 
 import java.util.zip.ZipException
 
@@ -235,7 +235,7 @@ class JRubyJarCopyAction implements CopyAction {
             // that use the constant pool to determine the dependencies of a class.
             ClassWriter cw = new ClassWriter(0)
 
-            ClassVisitor cv = new RemappingClassAdapter(cw, remapper)
+            ClassVisitor cv = new ClassRemapper(cw, remapper)
 
             try {
                 cr.accept(cv, ClassReader.EXPAND_FRAMES)