pw_presubmit: Exclude patches from copyright check

Change-Id: Ie763b0c8ebb3168286d58de959628de6d96e1cdc
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/28340
Pigweed-Auto-Submit: Rob Mohr <mohrr@google.com>
Reviewed-by: Anthony DiGirolamo <tonymd@google.com>
Commit-Queue: Auto-Submit <auto-submit@pigweed.google.com.iam.gserviceaccount.com>
diff --git a/pw_presubmit/py/pw_presubmit/pigweed_presubmit.py b/pw_presubmit/py/pw_presubmit/pigweed_presubmit.py
index b31a315..d75f498 100755
--- a/pw_presubmit/py/pw_presubmit/pigweed_presubmit.py
+++ b/pw_presubmit/py/pw_presubmit/pigweed_presubmit.py
@@ -281,6 +281,9 @@
     r'\.pb\.h$',
     r'\.pb\.c$',
     r'\_pb2.pyi?$',
+    # Diff/Patch files
+    r'\.diff$',
+    r'\.patch$',
 )