Update STOPS emails

Fixes https://magfest.atlassian.net/browse/MAGDEV-1336.

magprime/templates/emails/shifts/created.txt

@@ -1,6 +1,6 @@
 {{ attendee.first_name }},
 
-Thanks for signing up to volunteer at {{ c.EVENT_NAME }}!  You're currently assigned to the {{ attendee.assigned_depts_labels|readable_join }} department{{ attendee.assigned_depts_labels|length|pluralize }}, but let us know if you'd also like to work in any other departments.
+Thanks for signing up to volunteer at {{ c.EVENT_NAME }}! You're currently assigned to the {{ attendee.assigned_depts_labels|readable_join }} department{{ attendee.assigned_depts_labels|length|pluralize }}, but let us know if you'd also like to work in any other departments.
 
 You can {% if attendee.badge_type == c.STAFF_BADGE %}request staff crash space and {% endif %}sign up for shifts at {{ c.URL_BASE }}/staffing/login?first_name={{ attendee.first_name|urlencode }}&last_name={{ attendee.last_name|urlencode }}&email={{ attendee.email|urlencode }}&zip_code={{ attendee.zip_code|urlencode }} -- if you need to, you can verify/update your personal information at {{ c.URL_BASE }}/preregistration/confirm?id={{ attendee.id }}. Some shifts have not been created yet - check back later for updates.
 

magprime/templates/emails/shifts/reminder.txt

@@ -4,7 +4,7 @@ Thanks again for signing up to volunteer at {{ c.EVENT_NAME }}!  You are not cur
 
 Please sign up for shifts at {{ c.URL_BASE }}/staffing/login?first_name={{ attendee.first_name|urlencode }}&last_name={{ attendee.last_name|urlencode }}&email={{ attendee.email|urlencode }}&zip_code={{ attendee.zip_code|urlencode }} -- if you need to, you can verify/update your personal information at {{ c.URL_BASE }}/preregistration/confirm?id={{ attendee.id }}
 
-You can drop shifts up until 11:59pm on January 11. You can continue to add shifts up until and through the event. After that time, you will need to contact STOPS at {{ c.STAFF_EMAIL|email_only }}.
+You can drop shifts up until {{ c.DROP_SHIFTS_DEADLINE.astimezone(c.EVENT_TIMEZONE).strftime('%B %-e') }}. After that time, you will need to contact STOPS at {{ c.STAFF_EMAIL|email_only }}. You can continue to add shifts up until and through the event.
 
 Please let us know if you have any questions.