feat(interfaces): add IUserUpdate interface

This commit introduces a new interface named IUserUpdate. This interface consists of optional properties like id, username, firstname, lastname, dob and gdpr. These properties are used for validating user's data during update operation.

Issue: #18
Signed-off-by: Mathis <yidhra@tuta.io>

src/interfaces/services/IUserUpdate.ts

@@ -0,0 +1,8 @@
+export interface IUserUpdate {
+	id?: string;
+	username?: string;
+	firstname?: string;
+	lastname?: string;
+	dob?: Date;
+	gdpr?: Date;
+}