Prepare 2.5.1 (#204)

Release v2.5.0 (#195)

* Ignore built gems from git

* Prepare v2.5.0

Prepare 2.4.1

Prepare v.2.4.0 (#186)

Prepare version 2.3.1

Prep for 2.3.0

Bump to v2.2.1

Bump to version 2.2.0

v2.1.0

2.1.0 (2016-12-22)
==================
- Fixed a NoMethodError that might occur when using the NetHttp Driver (#130 grahamkenville)
- More securely compare signatures in a way that prevents timing attacks (#56 leishman, #133 will0)
- Remove support for MD2 and MD4 hashing algorithms since they are insecure (#134 will0)
- Disallow requests that are too far in the future to limit the time available for a brute force signature guess (#119 fwininger)

2.0.1 (2016-07-25)

==================
- Support of `api_auth_options` in ActiveResource integration (#102 fwininger)
- Replace use of `#blank?` with `#nil?` to not depend on ActiveSupport (#114 packrat386)
- Fix Auth header matching to not match invalid SHA algorithms (#115 packrat386)
- Replace `alias_method_chain` with `alias_method` in the railtie since
  alias_method_chain is deprecated in Rails 5 (#118 mlarraz)