Regression: error on TAA accept endpoint

[dbluhm]

On main, I'm currently getting this error when attempting to accept the TAA through the admin API:

alice_1             | Traceback (most recent call last):
alice_1             |   File "/root/.cache/pypoetry/virtualenvs/aries-cloudagent-il7asoJj-py3.9/lib/python3.9/site-packages/aiohttp/web_protocol.py", line 433, in _handle_request
alice_1             |     resp = await request_handler(request)
alice_1             |   File "/root/.cache/pypoetry/virtualenvs/aries-cloudagent-il7asoJj-py3.9/lib/python3.9/site-packages/aiohttp/web_app.py", line 504, in _handle
alice_1             |     resp = await handler(request)
alice_1             |   File "/root/.cache/pypoetry/virtualenvs/aries-cloudagent-il7asoJj-py3.9/lib/python3.9/site-packages/aiohttp/web_middlewares.py", line 117, in impl
alice_1             |     return await handler(request)
alice_1             |   File "/aries_cloudagent/admin/server.py", line 178, in ready_middleware
alice_1             |     return await handler(request)
alice_1             |   File "/aries_cloudagent/admin/server.py", line 215, in debug_middleware
alice_1             |     return await handler(request)
alice_1             |   File "/root/.cache/pypoetry/virtualenvs/aries-cloudagent-il7asoJj-py3.9/lib/python3.9/site-packages/aiohttp_apispec/middlewares.py", line 45, in validation_middleware
alice_1             |     return await handler(request)
alice_1             |   File "/aries_cloudagent/admin/server.py", line 446, in setup_context
alice_1             |     return await task
alice_1             |   File "/usr/local/lib/python3.9/asyncio/futures.py", line 284, in __await__
alice_1             |     yield self  # This tells Task to wait for completion.
alice_1             |   File "/usr/local/lib/python3.9/asyncio/tasks.py", line 328, in __wakeup
alice_1             |     future.result()
alice_1             |   File "/usr/local/lib/python3.9/asyncio/futures.py", line 201, in result
alice_1             |     raise self._exception
alice_1             |   File "/usr/local/lib/python3.9/asyncio/tasks.py", line 256, in __step
alice_1             |     result = coro.send(None)
alice_1             |   File "/aries_cloudagent/ledger/routes.py", line 687, in ledger_accept_taa
alice_1             |     await ledger.accept_txn_author_agreement(
alice_1             |   File "/aries_cloudagent/ledger/indy_vdr.py", line 935, in accept_txn_author_agreement
alice_1             |     accept_time = self.taa_rough_timestamp()
alice_1             |   File "/aries_cloudagent/ledger/indy_vdr.py", line 926, in taa_rough_timestamp
alice_1             |     date.today(), datetime.min.time(), datetime.timezone.utc
alice_1             | AttributeError: type object 'datetime.datetime' has no attribute 'timezone'

I think this is related to the changes made in PR #2420