Upgrade rust/crates/rand_xorshift to 0.3.0

Test: make
Change-Id: I1d2d73bec75171071ecc96fd7eb6fd499bbccf83
diff --git a/Android.bp b/Android.bp
index 4c05bab..6ad2307 100644
--- a/Android.bp
+++ b/Android.bp
@@ -63,5 +63,5 @@
 // dependent_library ["feature_list"]
 //   bincode-1.3.1
 //   byteorder-1.3.4 "default,std"
-//   rand_core-0.5.1
+//   rand_core-0.6.0
 //   serde-1.0.118 "default,std"