[docs] Add integration test example to copy pasta template (#5961)

Co-authored-by: Julien Chaumond <chaumond@gmail.com>

examples/deebert/test_glue_deebert.py

@@ -5,6 +5,7 @@ import unittest
 from unittest.mock import patch
 
 import run_glue_deebert
+from transformers.testing_utils import slow
 
 
 logging.basicConfig(level=logging.DEBUG)
@@ -20,6 +21,7 @@ def get_setup_file():
 
 
 class DeeBertTests(unittest.TestCase):
+    @slow
     def test_glue_deebert(self):
         stream_handler = logging.StreamHandler(sys.stdout)
         logger.addHandler(stream_handler)