Fix dateformats

Setra expects datetime.datetime, not datetime.date
In addition, voucherdate is in fact not optional.

setra_client/models.py

@@ -33,7 +33,7 @@ class BaseModel(pydantic.BaseModel):
 class Transaction(BaseModel):
     account: str
     amount: float
-    transdate: Optional[datetime.date]
+    transdate: Optional[datetime.datetime]
     curamount: Optional[float]
     currency: Optional[str]
     description: str
@@ -51,7 +51,7 @@ class Transaction(BaseModel):
 
 
 class Voucher(BaseModel):
-    voucherdate: Optional[datetime.date]
+    voucherdate: datetime.datetime
     exref: Optional[str]
     voucherno: int
     transactions: typing.List[Transaction]

tests/fixtures/batch_with_voucher_fixture.json

@@ -8,12 +8,12 @@
     {
       "exref": 1,
       "voucherno": 66,
+      "voucherdate": "2020-10-14 00:00",
       "transactions": [
         {
-          "voucherid": 66,
           "account": 1,
           "amount": 1,
-          "transdate": 1,
+          "transdate": "2020-10-14 00:00",
           "curamount": 1,
           "currency": 1,
           "description": 1,
@@ -30,10 +30,9 @@
           "extinvref": 1
         },
         {
-          "voucherid": 66,
           "account": 2,
           "amount": 2,
-          "transdate": 2,
+          "transdate": "2020-10-14 00:00",
           "curamount": 2,
           "currency": 2,
           "description": 2,

tests/fixtures/voucher_fixture.json

 {
   "exref": 3,
   "voucherno": 4,
+  "voucherdate": "2020-10-14 00:00",
   "transactions": [
     {
       "voucherid": 66,