lib: constants: change DEPOT_TOOLS_DIR to Path

BUG=None
TEST=CQ passes

Change-Id: I561b931a4aead9c9b313315a2ca3daf4f1cc0b81
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/chromite/+/4374323
Reviewed-by: Lizzy Presland <zland@google.com>
Commit-Queue: Mike Frysinger <vapier@chromium.org>
Tested-by: Mike Frysinger <vapier@chromium.org>
diff --git a/scripts/fetch_cipd.py b/scripts/fetch_cipd.py
index 5fd36fb..b4a3705 100644
--- a/scripts/fetch_cipd.py
+++ b/scripts/fetch_cipd.py
@@ -13,7 +13,6 @@
 and ${version} is the version defined in CIPD.
 """
 
-import os
 import urllib.parse
 
 from chromite.lib import commandline
@@ -52,7 +51,7 @@
     try:
         cros_build_lib.run(
             [
-                os.path.join(constants.DEPOT_TOOLS_DIR, "cipd"),
+                constants.DEPOT_TOOLS_DIR / "cipd",
                 "pkg-fetch",
                 "-out",
                 options.output,