Fix error type serverless invoke

[thomas-tacquet]

Mentionned in #147

The error returned by function calls on serverless invoke command was not readable because of the wrong type.

After toString conversion :

 serverless invoke --function testfunc
[...]
AxiosError: Request failed with status code 403%

[Cubox]

Minor thing, but the % at the end of the message is due to zsh signaling there was no newline after that text.
Maybe add a \n after the text?

[thomas-tacquet]

Minor thing, but the % at the end of the message is due to zsh signaling there was no newline after that text. Maybe add a \n after the text?

Oh sure, fixed and tested 👌

serverless invoke --function testfunc
[...]
AxiosError: Request failed with status code 403