Upgrade gspread to latest

This newer version of the library requires a `Path` object, not just a
`str`, so update accordingly.

Author: DavidCain

poetry.lock

@@ -219,7 +219,7 @@ def update_participant(
 
     Much more efficient than updating the entire sheet.
     """
-    client = gspread.service_account(settings.OAUTH_JSON_CREDENTIALS)
+    client = gspread.service_account(Path(settings.OAUTH_JSON_CREDENTIALS))
     wks = client.open_by_key(discount.ga_key).sheet1
     writer = SheetWriter(discount, trust_cache=False)
 
@@ -250,7 +250,7 @@ def update_discount_sheet(discount: models.Discount, trust_cache: bool) -> None:
     For individual updates, this approach should be avoided (instead, opting to
     update individual cells in the spreadsheet).
     """
-    client = gspread.service_account(settings.OAUTH_JSON_CREDENTIALS)
+    client = gspread.service_account(Path(settings.OAUTH_JSON_CREDENTIALS))
     wks: gspread.worksheet.Worksheet = client.open_by_key(discount.ga_key).sheet1
     participants = list(
         discount.participant_set.select_related("membership", "user").order_by("name")