Use flexidate

Flexidate is a date parser that works well with date that out of
Python's built-in datetime package.

setup.py

@@ -12,6 +12,7 @@
           'singer-python==5.3.1',
           'psycopg2==2.7.4',
           'strict-rfc3339==0.7',
+          'flexidate==1.4',
       ],
       extras_require={
           'dev': [

tap_postgres/sync_strategies/logical_replication.py

@@ -8,7 +8,7 @@
 import singer.metadata as metadata
 import tap_postgres.db as post_db
 import tap_postgres.sync_strategies.common as sync_common
-from dateutil.parser import parse
+from flexidate import parse
 import psycopg2
 from psycopg2 import sql
 import copy