Return error tuple instead of raising errors

[gdub01]

I found I have to write extra code to handle the raises. This way the
user gets to choose whether to raise.

When googling around, noticed it was also brought up here:
https://elixirforum.com/t/error-handling-with-tesla/4511/4

[teamon]

This issue has been brought up in the past - #64
Please mind that changing this behaviour would be a major breaking change.
I'm open to changes, but there must a be good reason for them.

The current behaviour is to return %Tesla.Env on successful transaction and raise on adapter/connection errors. As you can is in #64 it is trivial to change this behaviour with a middleware and does not require any changes to the core.

[gdub01]

ahh - sorry. Definitely should've thought of the middleware approach. I may close this then as that will do the trick. Ty