Allow setting max message size

[lukebakken]

Fixes #47

Bump gen_smtp to 1.2.0

cc @a-marcellini @mforde84

[lukebakken]

@a-marcellini you should be able to build from this branch and test the new setting. That would help me out a lot. I have to figure out why the Erlang 23 and 24 test suites won't complete.

[a-marcellini]

Thank's @lukebakken! We'll try and report you the outcome.

[lukebakken]

@a-marcellini this pull request is complete. Please let me know the outcome of your test or if you have any issues.

[lukebakken]

@a-marcellini any update?

[a-marcellini]

@a-marcellini any update?

Hi, I'managed to build and test your update, and I can say that it works like a charm!
Great job!
The only problem we are experiencing is the multiarch build of the docker image. It thows a segmentation fault for arm arch., problably because of a bug of erlang, that, if we caught it right, they fixed a few days ago:
erlang/otp#6340

[lukebakken]

Thank you for testing @a-marcellini

[lukebakken]

@mforde84 @a-marcellini - https://github.com/gotthardp/rabbitmq-email/releases/tag/v1.1.0

[a-marcellini]

I've found a strange problem with the new release: if I use a client to send an email to rabbit directly it works.
However, if it is a mail server (postfix) that forward the same mail to rabbit, using it as a relay, it doesn't work.
Moreover:
If I use telnet:

telnet <rabbitserver> <mailport>

The strange answer is:

EHLO MyServer
250-mail.local
250-AUTH PLAIN LOGIN
250-SIZE 41943040
250-SIZE 10485760
250-8BITMIME
250-PIPELINING
250 SMTPUTF8

Where 41943040 is the message size I put in rabbit.config while 10485760 is the default gen_smtp size, I suppose.

[lukebakken]

@a-marcellini please open a new issue with those details:

https://github.com/gotthardp/rabbitmq-email/issues