Issue #69: Fixed SenderError in register example

A BeskarError is being raised as a result of SenderError in the
async_sender library when running the register example; this is because
the Message being sent does not have the to, cc or bcc attributes as
consequence of being reinitialised.

This was resolved by directly adding the Message arguements to the
`self.app.ctx.mail.send_message()` method.

Also:
* Changed the `reply_to` value from a list to a str
* Changed the response on the `/register` endpoint to JSONResponse

example/register.py

@@ -4,6 +4,7 @@
 import sanic_beskar
 from async_sender import Mail  # type: ignore
 from sanic import Sanic, json
+from sanic.response.types import JSONResponse
 from sanic_beskar import Beskar
 from tortoise import fields
 from tortoise.contrib.sanic import register_tortoise
@@ -243,9 +244,9 @@ async def register(request):
             roles="operator",
         )
 
-        await _guard.send_registration_email(email, user=new_user)
+        await _guard.send_registration_email(email, user=new_user, confirmation_sender="you@whatever.com")
         ret = {"message": f"successfully sent registration email to user {new_user.username}"}
-        return (json(ret), 201)
+        return JSONResponse(ret, 201)
 
     @sanic_app.route("/finalize")
     async def finalize(*args):

sanic_beskar/base.py

@@ -1798,18 +1798,15 @@ async def send_token_email(
             jinja_tmpl = jinja2.Template(template, autoescape=True, enable_async=True)
             notification["message"] = (await jinja_tmpl.render_async(notification)).strip()
 
-            _mail = import_module(self.app.ctx.mail.__module__)
-            msg = _mail.Message(
+            logger.debug(f"Sending email to {email}")
+            notification["result"] = await self.app.ctx.mail.send_message(
                 subject=notification["subject"],
                 to=[notification["email"]],
                 from_address=action_sender,
                 html=notification["message"],
-                reply_to=[action_sender],
+                reply_to=action_sender
             )
 
-            logger.debug(f"Sending email to {email}")
-            notification["result"] = await self.app.ctx.mail.send_message(msg)
-
         return notification
 
     async def get_user_from_registration_token(self, token: str) -> Any: