fix failing test

https://github.com/binaryornot/binaryornot/commit/38dee57986c6679d9936a1da6f6c8182da3734f8

Index: tests/test_check.py
--- tests/test_check.py.orig
+++ tests/test_check.py
@@ -216,7 +216,7 @@ def bytes_in_file(data):
 
 
 class TestDetectionProperties(unittest.TestCase):
-    @given(binary(average_size=512))
+    @given(binary(max_size=512))
     def test_never_crashes(self, data):
         with bytes_in_file(data) as f:
             is_binary(f)
