Add Cargo.lock and target/ to .gitignore

Change-Id: If49aae6bc09875dad79b0dffa3712bb12b0fc378
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/822456
Reviewed-by: Kevin Lubick <kjlubick@google.com>
Auto-Submit: Brian Osman <brianosman@google.com>
Commit-Queue: Kevin Lubick <kjlubick@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
diff --git a/.gitignore b/.gitignore
index 241f8fb..42155f6 100644
--- a/.gitignore
+++ b/.gitignore
@@ -60,5 +60,8 @@
 
 bazel-*
 
+Cargo.lock
+target/
+
 # A user is free to specify custom builds or options here without them being checked in.
 bazel/user/buildrc