pre-upload: include GN files in license checks

BUG=chromium:1098010
TEST=`repo upload` works

Change-Id: I328b1737ba885849105d5d5f0c8ebe5294053f0c
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/repohooks/+/3894032
Commit-Queue: Alex Klein <saklein@chromium.org>
Reviewed-by: Alex Klein <saklein@chromium.org>
Auto-Submit: Mike Frysinger <vapier@chromium.org>
Tested-by: Mike Frysinger <vapier@chromium.org>
diff --git a/pre-upload.py b/pre-upload.py
index b2f4923..5cfa27d 100755
--- a/pre-upload.py
+++ b/pre-upload.py
@@ -111,6 +111,8 @@
     # COMMON_EXCLUDED_LIST below.
     r"(^|.*[\\\/])[^.]+$",
     # Other
+    r".*\.gn",
+    r".*\.gni",
     r".*\.java$",
     r".*\.mk$",
     r".*\.am$",