Current version of singer fails due to missing pytz dependency

[Limess]

This can be fixed by using the latest singer version and also bumping backoff to an acceptable version

[2022-02-10, 12:08:44 GMT] {{subprocess.py:74}} INFO - Running command: ['bash', '-c', '/virtualenvs/tap-redshift/bin/tap-redshift --config /tmp/***tmp_singer_tap-redshift_config_4yf3rekf.json --discover > /tmp/***tmp_singer_tap-redshift_catalog__ufmzsfk.json']
[2022-02-10, 12:08:44 GMT] {{subprocess.py:85}} INFO - Output:
[2022-02-10, 12:08:44 GMT] {{subprocess.py:89}} INFO - Traceback (most recent call last):
[2022-02-10, 12:08:44 GMT] {{subprocess.py:89}} INFO -   File "/virtualenvs/tap-redshift/bin/tap-redshift", line 5, in <module>
[2022-02-10, 12:08:44 GMT] {{subprocess.py:89}} INFO -     from tap_redshift import main
[2022-02-10, 12:08:44 GMT] {{subprocess.py:89}} INFO -   File "/virtualenvs/tap-redshift/lib/python3.9/site-packages/tap_redshift/__init__.py", line 30, in <module>
[2022-02-10, 12:08:44 GMT] {{subprocess.py:89}} INFO -     import singer
[2022-02-10, 12:08:44 GMT] {{subprocess.py:89}} INFO -   File "/virtualenvs/tap-redshift/lib/python3.9/site-packages/singer/__init__.py", line 1, in <module>
[2022-02-10, 12:08:44 GMT] {{subprocess.py:89}} INFO -     from singer import utils
[2022-02-10, 12:08:44 GMT] {{subprocess.py:89}} INFO -   File "/virtualenvs/tap-redshift/lib/python3.9/site-packages/singer/utils.py", line 8, in <module>
[2022-02-10, 12:08:44 GMT] {{subprocess.py:89}} INFO -     import pytz
[2022-02-10, 12:08:44 GMT] {{subprocess.py:89}} INFO - ModuleNotFoundError: No module named 'pytz'
[2022-02-10, 12:08:44 GMT] {{subprocess.py:93}} INFO - Command exited with return code 1
[2022-02-10, 12:08:44 GMT] {{taskinstance.py:1700}} ERROR - Task failed with exception

[Limess]

For reference, we got this tap working by updating all dependencies, and merging existing PRs on our fork: https://github.com/signal-ai/tap-redshift