Fix deprecation warnings: 'assertEquals' in tests and 'sudo' in travis.

Author: arnau126

.travis.yml

@@ -1,5 +1,4 @@
 language: python
-sudo: false
 dist: xenial
 cache: false
 before_install:

t/unit/test_admin.py

@@ -81,7 +81,7 @@ class ValidateUniqueTests(TestCase):
     def test_validate_unique_raises_if_schedule_not_set(self):
         with self.assertRaises(ValidationError) as cm:
             PeriodicTask(name='task0').validate_unique()
-        self.assertEquals(
+        self.assertEqual(
             cm.exception.args[0],
             'One of clocked, interval, crontab, or solar must be set.',
         )
@@ -103,9 +103,9 @@ def test_validate_unique_raises_for_multiple_schedules(self):
             with self.assertRaises(ValidationError) as cm:
                 PeriodicTask(name=name, **options_dict).validate_unique()
             errors = cm.exception.args[0]
-            self.assertEquals(errors.keys(), options_dict.keys())
+            self.assertEqual(errors.keys(), options_dict.keys())
             for error_msg in errors.values():
-                self.assertEquals(error_msg, [expected_error_msg])
+                self.assertEqual(error_msg, [expected_error_msg])
 
     def test_validate_unique_not_raises(self):
         PeriodicTask(crontab=CrontabSchedule()).validate_unique()