Change publish to use call

[dantswain]

In reference to discussion on #20 - this should be safer in high-throughput situations.

[dantswain]

Thanks @pma! Will you be doing a release any time soon?

[pma]

@ono amqp_client 3.6.8 is hex. I have updated the deps and prepared to release 0.2.0. Let me know if you agree it's good to go.

/cc @dantswain

[ono]

@pma absolutely! using call here makes sense to me and glad to know amqp_client 3.6.8 is there! 🎉 please go ahead or let me know if you want me to do it.

[dantswain]

Thanks guys!