Fix the verify_upstream_binaries test by supplying an upstream
to fetch from.

Bug: https://github.com/flutter/flutter/issues/95297
Change-Id: I6401af828a9eaca906588a7c71eb4abaea955774
Reviewed-on: https://flutter-review.googlesource.com/c/recipes/+/34180
Commit-Queue: Xilai Zhang <xilaizhang@google.com>
Reviewed-by: Xilai Zhang <xilaizhang@google.com>
diff --git a/recipe_modules/adhoc_validation/resources/verify_binaries_codesigned.sh b/recipe_modules/adhoc_validation/resources/verify_binaries_codesigned.sh
index b3dae12..acf3a66 100644
--- a/recipe_modules/adhoc_validation/resources/verify_binaries_codesigned.sh
+++ b/recipe_modules/adhoc_validation/resources/verify_binaries_codesigned.sh
@@ -14,4 +14,4 @@
   exit 1
 fi
 # Run the actual validation.
-./dev/conductor/bin/conductor codesign --verify --revision $REVISION
+./dev/conductor/bin/conductor codesign --verify --revision $REVISION --upstream='https://github.com/flutter/flutter.git'