Require ruby 2.0.0, stopped supporting 1.9.3.

because of the "api:" keyword argument
BTW 2.0.0 support ended on 2016-02-24:
https://www.ruby-lang.org/en/news/2016/02/24/support-plan-of-ruby-2-0-0-and-2-1/

Author: mvidner

.travis.yml

@@ -4,14 +4,12 @@ rvm:
   - "2.2.5"
   - "2.1.10"
   - "2.0.0"
-  - "1.9.3"
   - jruby-9.0.5.0
   - ruby-head
   - rbx
 gemfile: Gemfile.ci
 matrix:
   allow_failures:
-    - rvm: "1.9.3"
     - rvm: jruby-9.0.5.0
     - rvm: ruby-head
     - rvm: rbx

NEWS

@@ -11,6 +11,9 @@ API:
  * Added proxy objects whose methods return single values instead of arrays
    (use Service#[] instead of Service#object; Issue#30).
 
+Requirements:
+ * Require ruby 2.0.0, stopped supporting 1.9.3.
+
 == Ruby D-Bus 0.11.2 - 2016-09-11
 
 Bug fixes:

README.md

@@ -43,7 +43,7 @@ via [UPower](http://upower.freedesktop.org/docs/UPower.html#UPower:OnBattery)
 
 ## Requirements
 
-- Ruby 1.9.3 or 2.0
+- Ruby 2.0 or newer.
 
 
 ## Installation

doc/Reference.md

@@ -204,7 +204,7 @@ If the signature expects a Variant
 
 If a byte array (`ay`) is expected you can pass a String too.
 The bytes sent are according to the string's
-[encoding](http://ruby-doc.org/core-1.9.3/Encoding.html).
+[encoding](http://ruby-doc.org/core-2.0.0/Encoding.html).
 
 ##### nil
 

package/rubygem-ruby-dbus.spec

@@ -38,7 +38,7 @@ BuildRequires:  netcfg
 # /MANUAL
 BuildRoot:      %{_tmppath}/%{name}-%{version}-build
 BuildRequires:  ruby-macros >= 5
-BuildRequires:  %{ruby >= 1.9.3}
+BuildRequires:  %{ruby >= 2.0.0}
 BuildRequires:  %{rubygem gem2rpm}
 Url:            https://trac.luon.net/ruby-dbus
 Source:         http://rubygems.org/gems/%{mod_full_name}.gem

ruby-dbus.gemspec

@@ -14,7 +14,7 @@ GEMSPEC = Gem::Specification.new do |s|
   s.homepage = "https://trac.luon.net/ruby-dbus"
   s.files = FileList["{doc,examples,lib,spec}/**/*", "COPYING", "NEWS", "Rakefile", "README.md", "ruby-dbus.gemspec", "VERSION", ".rspec"].to_a.sort
   s.require_path = "lib"
-  s.required_ruby_version = ">= 1.9.3"
+  s.required_ruby_version = ">= 2.0.0"
   s.add_development_dependency("packaging_rake_tasks")
   s.add_development_dependency("rspec")
 end