Change gemspec dependencies to '>= 1.99', '< 3' in prep for 2.0.0.beta release.

Author: gkellogg

Gemfile

@@ -4,6 +4,7 @@ gemspec
 
 gem "rdf",            git: "git://github.com/ruby-rdf/rdf.git", branch: "develop"
 gem "rdf-spec",       git: "git://github.com/ruby-rdf/rdf-spec.git", branch: "develop"
+gem 'rdf-isomorphic', git: "git://github.com/ruby-rdf/rdf-isomorphic.git", branch: "develop"
 
 group :debug do
   gem "byebug", platforms: :mri

rdf-mongo.gemspec

@@ -29,10 +29,10 @@ Gem::Specification.new do |gem|
 
   gem.required_ruby_version      = '>= 2.0'
   gem.requirements               = []
-  gem.add_runtime_dependency     'rdf',             '~> 1.99'
+  gem.add_runtime_dependency     'rdf',             '>= 1.99', '< 3'
   gem.add_runtime_dependency     'mongo',           '~> 1.10'
 
-  gem.add_development_dependency 'rdf-spec',        '~> 1.99'
+  gem.add_development_dependency 'rdf-spec',        '>= 1.99', '< 3'
   gem.add_development_dependency 'rspec',           '~> 3.0'
   gem.add_development_dependency 'rspec-its',       '~> 1.0'
   gem.add_development_dependency 'yard' ,           '~> 0.8'