Remove 1.8.7 and ree fom Travis because it does not support them anymore. Adapt json for jruby as well to prevent unexpected tPOW error

Author: pitbulk

.travis.yml

@@ -1,6 +1,5 @@
 language: ruby
 rvm:
-  - 1.8.7
   - 1.9.3
   - 2.0.0
   - 2.1.10
@@ -11,7 +10,6 @@ rvm:
   - 2.6.6
   - 2.7.2
   - 3.0.0
-  - ree
   - jruby-1.7.27
   - jruby-9.1.17.0
   - jruby-9.2.13.0
@@ -22,10 +20,6 @@ before_install:
   - gem update bundler
 matrix:
   exclude:
-    - rvm: 1.8.7
-      gemfile: Gemfile
-    - rvm: ree
-      gemfile: Gemfile
     - rvm: jruby-1.7.27
       gemfile: gemfiles/nokogiri-1.5.gemfile
     - rvm: jruby-9.1.17.0
@@ -34,6 +28,8 @@ matrix:
       gemfile: gemfiles/nokogiri-1.5.gemfile
     - rvm: 2.1.5
       gemfile: gemfiles/nokogiri-1.5.gemfile
+    - rvm: 2.1.10
+      gemfile: gemfiles/nokogiri-1.5.gemfile
     - rvm: 2.2.10
       gemfile: gemfiles/nokogiri-1.5.gemfile
     - rvm: 2.3.8

ruby-saml.gemspec

@@ -31,6 +31,7 @@ Gem::Specification.new do |s|
     if JRUBY_VERSION < '9.2.0.0'
       s.add_runtime_dependency('nokogiri', '>= 1.8.2', '<= 1.8.5')
       s.add_runtime_dependency('jruby-openssl', '>= 0.9.8')
+      s.add_runtime_dependency('json', '< 2.3.0')
     else
       s.add_runtime_dependency('nokogiri', '>= 1.8.2')
     end
@@ -39,7 +40,7 @@ Gem::Specification.new do |s|
     s.add_runtime_dependency('nokogiri', '<= 1.5.11')
   elsif RUBY_VERSION < '2.1'
     s.add_runtime_dependency('nokogiri', '>= 1.5.10', '<= 1.6.8.1')
-    s.add_runtime_dependency('json', '< 2.2.0')
+    s.add_runtime_dependency('json', '< 2.3.0')
   elsif RUBY_VERSION < '2.3'
     s.add_runtime_dependency('nokogiri', '>= 1.9.1', '<= 1.10.0')
   else