Remove EncryptedFile.created_at (not in API), fix README

Author: Fivell

README.md

@@ -395,7 +395,7 @@ The SDK distinguishes between date-only and datetime fields:
 
 - **Datetime fields** are deserialized as `datetime.datetime` with `timezone.utc`:
   - `Did.created_at`, `Did.expires_at`
-  - `EncryptedFile.created_at`, `EncryptedFile.expire_at`
+  - `EncryptedFile.expire_at`
   - `DidReservation.created_at`, `DidReservation.expire_at`
   - `Proof.created_at`, `Proof.expires_at`
   - `Order.created_at`, `Identity.created_at`, `Address.created_at`, `VoiceInTrunk.created_at`, `VoiceInTrunkGroup.created_at`, `VoiceOutTrunk.created_at`, `SharedCapacityGroup.created_at`, `Export.created_at`, `AddressVerification.created_at`, `PermanentSupportingDocument.created_at`

src/didww/resources/encrypted_file.py

@@ -3,7 +3,6 @@
 
 class EncryptedFile(DidwwApiModel):
     description = SafeAttributeField("description")
-    created_at = DatetimeAttributeField("created_at")
     expire_at = DatetimeAttributeField("expire_at")
 
     class Meta: