releasetools: img_from_target_files uses zip2zip.

Test: Build the following targets and check the built image archive.
      bonito-userdebug (contains flashable images);
      cf_x86_phone-userdebug (contains super.img);
      aosp_arm64-eng (contains VerifiedBootParams.textproto)
Test: m -j otatools-package; Check that zip2zip is included; Use
      bin/img_from_target_files to generate image archive.
Change-Id: I9f28765bd702849f0df309faebd6aa3072920536
diff --git a/tools/releasetools/Android.bp b/tools/releasetools/Android.bp
index fa65767..3308f3d 100644
--- a/tools/releasetools/Android.bp
+++ b/tools/releasetools/Android.bp
@@ -73,6 +73,9 @@
         "releasetools_build_super_image",
         "releasetools_common",
     ],
+    required: [
+        "zip2zip",
+    ],
 }
 
 python_defaults {