Ignore error raised from enum

Not sure this is the correct place to suppress it but...

E               Traceback (most recent call last):
E                 File "/opt/python/3.8.7/lib/python3.8/enum.py", line 339, in __call__
E                   return cls.__new__(cls, value)
E               ResourceWarning: unclosed file <_io.TextIOWrapper
                  name='_test_cgi_form/db/lock' mode='w' encoding='UTF-8'>

Author: rouilj

.travis.yml

@@ -152,6 +152,7 @@ script:
     -W "ignore:the imp module:DeprecationWarning:gpg.gpgme:15" 
     -W "ignore:'U' mode::docutils.io" 
     -W "ignore:unclosed:ResourceWarning:roundup.roundup.demo" 
+    -W "ignore:unclosed file:ResourceWarning:enum" 
     -v --maxfail=20 test/ --cov=roundup
 
 after_success: