TZ environment key does not work on 2.0 macOS builds. In order to set the timezone, you'll need to add the following command to your configuration:
# Set Timezone - run: name: set timezone command: | sudo systemsetup -settimezone "$TIMEZONE"
$TIMEZONE with whatever timezone you want to use. You can get a list of all supported timezones with
sudo systemsetup -listtimezones.