Relax dependencies for 3.0 release.

Author: gkellogg

json-ld.gemspec

@@ -26,19 +26,27 @@ Gem::Specification.new do |gem|
 
   gem.required_ruby_version = '>= 2.2.2'
   gem.requirements          = []
-  gem.add_runtime_dependency     'rdf',             '~> 2.2', '>= 2.2.8'
+  #gem.add_runtime_dependency     'rdf',             '~> 3.0'
+  gem.add_runtime_dependency     'rdf',             '>= 2.2.8', '< 4.0'
   gem.add_runtime_dependency     'multi_json',      '~> 1.12'
-  gem.add_development_dependency 'linkeddata',      '~> 2.2'
+  #gem.add_development_dependency 'linkeddata',      '~> 2.2'
+  gem.add_development_dependency 'linkeddata',      '>= 2.2', '< 4.0'
   gem.add_development_dependency 'jsonlint',        '~> 0.2'  unless RUBY_ENGINE == "jruby"
-  gem.add_development_dependency 'oj',              '~> 2.17' unless RUBY_ENGINE == "jruby"
+  gem.add_development_dependency 'oj',              '~> 2.18' unless RUBY_ENGINE == "jruby"
   gem.add_development_dependency 'yajl-ruby',       '~> 1.2'  unless RUBY_ENGINE == "jruby"
-  gem.add_development_dependency 'rdf-isomorphic',  '~> 2.0'
-  gem.add_development_dependency 'rdf-spec',        '~> 2.2'
-  gem.add_development_dependency 'rdf-trig',        '~> 2.0'
-  gem.add_development_dependency 'rdf-turtle',      '~> 2.0'
-  gem.add_development_dependency 'rdf-vocab',       '~> 2.0'
-  gem.add_development_dependency 'rdf-xsd',         '~> 2.0'
-  gem.add_development_dependency 'rspec',           '~> 3.5'
+  #gem.add_development_dependency 'rdf-isomorphic',  '~> 3.0'
+  #gem.add_development_dependency 'rdf-spec',        '~> 3.0'
+  #gem.add_development_dependency 'rdf-trig',        '~> 3.0'
+  #gem.add_development_dependency 'rdf-turtle',      '~> 3.0'
+  #gem.add_development_dependency 'rdf-vocab',       '~> 3.0'
+  #gem.add_development_dependency 'rdf-xsd',         '~> 3.0'
+  gem.add_development_dependency 'rdf-isomorphic',  '>= 2.0', '< 4.0'
+  gem.add_development_dependency 'rdf-spec',        '>= 2.2', '< 4.0'
+  gem.add_development_dependency 'rdf-trig',        '>= 2.2', '< 4.0'
+  gem.add_development_dependency 'rdf-turtle',      '>= 2.2', '< 4.0'
+  gem.add_development_dependency 'rdf-vocab',       '>= 2.2', '< 4.0'
+  gem.add_development_dependency 'rdf-xsd',         '>= 2.2', '< 4.0'
+  gem.add_development_dependency 'rspec',           '~> 3.7'
   gem.add_development_dependency 'rspec-its',       '~> 1.2'
   gem.add_development_dependency 'yard' ,           '~> 0.8'