fix utf-8 test by using another locale

The pt_BR locale had the weekday capitalization changed [1]. That means that depending on libc version (-> Travis build tests vs Fedora 29) the test either was successull or failed [2].

[1]: https://sourceware.org/git/?p=glibc.git;a=commit;h=686db256f640372df81242bf20d458f54e069f56
[2]: commit e05f4f3

re commit e05f4f3

Author: FlorianMickler

tests/test_liborgdate_utf8.py

@@ -18,7 +18,7 @@ class OrgDateUtf8TestCase(unittest.TestCase):
 	Tests OrgDate with utf-8 enabled locales
 	"""
 	LOCALE_LOCK = threading.Lock()
-	UTF8_LOCALE = "pt_BR.utf-8"
+	UTF8_LOCALE = "es_ES.utf-8"
 
 	@contextmanager
 	def setlocale(self, name):