Specify revisions in rebar dependencies

[wgslr]

Currently most of rebar dependencies in rebar.config do not have specified revision nor tag. Therefore sudden change in any of those dependencies might brake the erl-dns package and any other packages using it. Please specify those versions in every dependency.

[aeden]

I've specified them as master in cases where they were missing. If it becomes an issue to tie them to master then I'll start freezing to tags where necessary and possible.