Use zoned date time parsing

[wsargent]

Fixes #99

[orende]

@wsargent Good catch! It feels like this behavior (date parsing) should have been caught by a test before merge. Could you add a test for this? Either a unit test or Selenium test, whichever you prefer.

[wsargent]

This is a bit of a problem, because the admin selenium test doesn't work for me. This is straight from HEAD on the master branch:

[ERROR] Failures:
[ERROR]   AdminAcceptanceTest.adminSiteCanBookNewCargo:53
Expecting:
 <"01/06/2023">
to be equal to:
 <"31/05/2023">
but was not.

I think the problem is that I'm in San Francisco and some of the timezone logic is hardcoded for another timezone...

[orende]

This is a bit of a problem, because the admin selenium test doesn't work for me. This is straight from HEAD on the master branch:

[ERROR] Failures:
[ERROR]   AdminAcceptanceTest.adminSiteCanBookNewCargo:53
Expecting:
 <"01/06/2023">
to be equal to:
 <"31/05/2023">
but was not.

I think the problem is that I'm in San Francisco and some of the timezone logic is hardcoded for another timezone...

Sorry about the late reply to this, parental leave got in the way. We'll have to look into the hardcoded timezone and address it so that you can get the tests to pass.

[orende]

@wsargent Could you rebase this pull request on master now and see if the changes from #136 fixes the test failures?