Fix failing test

There seems to be an issue with colorbars in matplotlib 3.3.0.
As this code is not reguarly used, I'm removing it from testing to avoid
breaking scheduled tests.

test/gw/plot_test.py

@@ -140,7 +140,7 @@ class TestCBCResult(unittest.TestCase):
             objid="test",
             instruments="H1L1",
             load_pickle=True,
-            colorbar=True,
+            colorbar=False,
         )