update regex in modified time test to support + or - timezone offsets vs. UTC

Author: chrissimpkins

tests/test_utils.py

@@ -9,7 +9,7 @@
 def test_get_file_modtime():
     modtime = get_file_modtime(os.path.join("tests", "testfiles", "test.txt"))
     assert modtime.startswith("2019-09-0") is True
-    regex = re.compile(r"""\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}\.\d+-\d{2}:\d{2}""")
+    regex = re.compile(r"""\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}\.\d+[-+]\d{2}:\d{2}""")
     assert regex.fullmatch(modtime) is not None