pre-upload: fix typo

BUG=none
TEST=none

Change-Id: Ie57e2caf6ea51e4f140e54afd5e2718d37b81152
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/repohooks/+/2375313
Commit-Queue: Tom Hughes <tomhughes@chromium.org>
Commit-Queue: Chris McDonald <cjmcdonald@chromium.org>
Tested-by: Tom Hughes <tomhughes@chromium.org>
Auto-Submit: Tom Hughes <tomhughes@chromium.org>
Reviewed-by: Chris McDonald <cjmcdonald@chromium.org>
diff --git a/pre-upload.py b/pre-upload.py
index e06b808..4adb9a5 100755
--- a/pre-upload.py
+++ b/pre-upload.py
@@ -6,7 +6,7 @@
 
 """Presubmit checks to run when doing `repo upload`.
 
-You can add new checks by adding a functions to the HOOKS constants.
+You can add new checks by adding a function to the HOOKS constants.
 """
 
 from __future__ import print_function