Move source backup in jar to backup directory (#826)

Include vendordeps and build.gradle and full source directory to make it
easier to restore from roboRIO jar.
Fixes wpilibsuite/GradleRIO#713

Author: sciencewhiz

vscode-wpilib/resources/gradle/java/build.gradle

@@ -90,6 +90,9 @@ wpi.sim.addDriverstation()
 jar {
     from { configurations.runtimeClasspath.collect { it.isDirectory() ? it : zipTree(it) } }
     from sourceSets.main.allSource
+    from('src') { into 'backup/src' }
+    from('vendordeps') { into 'backup/vendordeps' }
+    from('build.gradle') { into 'backup' }
     manifest edu.wpi.first.gradlerio.GradleRIOPlugin.javaManifest(ROBOT_MAIN_CLASS)
     duplicatesStrategy = DuplicatesStrategy.INCLUDE
 }