vendor.py: send licenses to vendor_artifacts/

`./vendor.py` is going to produce a second file soon. Rather than
further cluttering the root directory with this kind of thing, make a
new home for it.

BUG=b:250919469
TEST=./vendor.py

Change-Id: Ifb20ca05d8bb03833f49c9eb4dcf9b26e5eadc95
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/rust_crates/+/4092859
Reviewed-by: Allen Webb <allenwebb@google.com>
Commit-Queue: George Burgess <gbiv@chromium.org>
Tested-by: George Burgess <gbiv@chromium.org>
diff --git a/vendor.py b/vendor.py
index 56fd0d6..2845b44 100755
--- a/vendor.py
+++ b/vendor.py
@@ -889,7 +889,9 @@
     patches = os.path.join(current_path, "patches")
     vendor = os.path.join(current_path, "vendor")
     crab_dir = os.path.join(current_path, "crab", "crates")
-    license_shorthand_file = os.path.join(current_path, "licenses_used.txt")
+    license_shorthand_file = os.path.join(
+        current_path, "vendor_artifacts", "licenses_used.txt"
+    )
 
     # First, actually run cargo vendor
     run_cargo_vendor(current_path)