fix: avoid making the parent directory redundantly in test case

tests/deploy.TestCase

@@ -122,7 +122,7 @@ class DeployTest(unittest.TestCase):
     def test_update_serverwebroot_in_index_only_mode(self):
         os.chdir(self.testdir)
         repo = Path('repo')
-        repo.mkdir(parents=True)
+        repo.mkdir()
         fake_apk = repo / 'fake.apk'
         with fake_apk.open('w') as fp:
             fp.write('not an APK, but has the right filename')