3.0 release dep updates and release notes

[btm]

Ruby dep updates
First release notes draft
Platform updates

[btm]

https://buildkite.com/chef/chef-opscode-pushy-server-master-omnibus-adhoc/builds/34

[btm]

This made it through build, but was failing in test: https://buildkite.com/chef/chef-opscode-pushy-server-master-omnibus-adhoc/builds/47#e533b183-bf16-4db7-9402-caf70b9d29ec/123-9334

Recipe: opscode-pushy-server::push_database
--
  | * opscode_pushy_server_pg_user[opscode_pushy] action create
  |  
  | ================================================================================
  | Error executing action `create` on resource 'opscode_pushy_server_pg_user[opscode_pushy]'
  | ================================================================================
  |  
  | ArgumentError
  | -------------
  | cannot set encoding on non-encoding capable object

[btm]

It looks like updating the pg gem fixed that issue. adhoc#48 is mostly successful, except for one tester messing up in an unrelated way. I'm restarting that tester, but either way we should be able to merge this and get a build now.

[PrajaktaPurohit]

Thank you!

[btm]

The el6 tester is not installing. I cant figure out why on my phone, so I'm going to merge this to get a non adhoc build and see if tha reproduces.