Update faraday requirement from ~> 0.9.0 to >= 0.9, < 0.18

Updates the requirements on [faraday](https://github.com/lostisland/faraday) to permit the latest version.
- [Release notes](https://github.com/lostisland/faraday/releases)
- [Changelog](https://github.com/lostisland/faraday/blob/master/CHANGELOG.md)
- [Commits](lostisland/faraday@v0.9.0...v0.17.0)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

alchemy-api-rb.gemspec

@@ -18,7 +18,7 @@ Gem::Specification.new do |gem|
 
   gem.required_ruby_version = '>= 2.2.9'
 
-  gem.add_dependency             'faraday',             '~> 0.9.0'
+  gem.add_dependency             'faraday',             '>= 0.9', '< 0.18'
   gem.add_dependency             'excon',               '~> 0.28'
 
   gem.add_development_dependency 'minitest',            '~> 5.4.0'