prep 3.x release

Author: oreoshake

CHANGELOG.md

@@ -1,3 +1,7 @@
+## 3.0.0
+
+secure_headers 3.0.0 is a near-complete, not-entirely-backward-compatible rewrite. Please see the [upgrade guide](https://github.com/twitter/secureheaders/blob/master/upgrading-to-3-0.md) for an in-depth explanation of the changes and the suggested upgrade path.
+
 ## 2.5.1 - 2016-02-16 18:11:11 UTC - Remove noisy deprecation warning
 
 See https://github.com/twitter/secureheaders/issues/203 and https://github.com/twitter/secureheaders/commit/cfad0e52285353b88e46fe384e7cd60bf2a01735

secure_headers.gemspec

@@ -1,7 +1,7 @@
 # -*- encoding: utf-8 -*-
 Gem::Specification.new do |gem|
   gem.name          = "secure_headers"
-  gem.version       = "3.0.0.rc1"
+  gem.version       = "3.0.0"
   gem.authors       = ["Neil Matatall"]
   gem.email         = ["[email protected]"]
   gem.description   = 'Security related headers all in one gem.'