Require Faraday >= 0.9.0 in gemspec

In #115 we started configuring Faraday to use the FlatParamsEncoder to
avoid an issue with dropped parameters when building a request url.

The FlatParamsEncoder was only added on Faraday 0.9.0 and thus we must
require it explicitly, otherwise clients may get confusing messages
after upgrading to hyperclient 0.8.4.

Fixes #117

Author: ivoanjo

CHANGELOG.md

@@ -1,5 +1,6 @@
 ### 0.8.4 (Next)
 
+* [#117](https://github.com/codegram/hyperclient/issues/117): Require Faraday >= 0.9.0 in gemspec - [@ivoanjo](https://github.com/ivoanjo).
 * Your contribution here.
 
 ### 0.8.3 (March 30, 2017)

hyperclient.gemspec

@@ -14,7 +14,7 @@ Gem::Specification.new do |gem|
   gem.require_paths = ['lib']
   gem.version       = Hyperclient::VERSION
 
-  gem.add_dependency 'faraday'
+  gem.add_dependency 'faraday', '>= 0.9.0'
   gem.add_dependency 'futuroscope'
   gem.add_dependency 'faraday_middleware'
   gem.add_dependency 'faraday_hal_middleware'