fix: Gemfile to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-RUBY-ACTIVESUPPORT-569598
- https://snyk.io/vuln/SNYK-RUBY-I18N-72582
- https://snyk.io/vuln/SNYK-RUBY-JSON-560838
- https://snyk.io/vuln/SNYK-RUBY-NOKOGIRI-1055008
- https://snyk.io/vuln/SNYK-RUBY-NOKOGIRI-20277
- https://snyk.io/vuln/SNYK-RUBY-NOKOGIRI-20299
- https://snyk.io/vuln/SNYK-RUBY-NOKOGIRI-20367
- https://snyk.io/vuln/SNYK-RUBY-NOKOGIRI-20368
- https://snyk.io/vuln/SNYK-RUBY-NOKOGIRI-20432
- https://snyk.io/vuln/SNYK-RUBY-NOKOGIRI-22013
- https://snyk.io/vuln/SNYK-RUBY-NOKOGIRI-22014
- https://snyk.io/vuln/SNYK-RUBY-NOKOGIRI-459107
- https://snyk.io/vuln/SNYK-RUBY-NOKOGIRI-534637
- https://snyk.io/vuln/SNYK-RUBY-NOKOGIRI-552159
- https://snyk.io/vuln/SNYK-RUBY-NOKOGIRI-72433
- https://snyk.io/vuln/SNYK-RUBY-OAUTH-1012727
- https://snyk.io/vuln/SNYK-RUBY-RACK-538324
- https://snyk.io/vuln/SNYK-RUBY-RACK-569066
- https://snyk.io/vuln/SNYK-RUBY-RACK-572377
- https://snyk.io/vuln/SNYK-RUBY-RACK-72567
- https://snyk.io/vuln/SNYK-RUBY-RACKPROTECTION-20394
- https://snyk.io/vuln/SNYK-RUBY-RACKPROTECTION-20395
- https://snyk.io/vuln/SNYK-RUBY-RACKPROTECTION-22019
- https://snyk.io/vuln/SNYK-RUBY-RUBYSAML-20269
- https://snyk.io/vuln/SNYK-RUBY-RUBYSAML-22020
- https://snyk.io/vuln/SNYK-RUBY-RUBYZIP-20336
- https://snyk.io/vuln/SNYK-RUBY-RUBYZIP-22039
- https://snyk.io/vuln/SNYK-RUBY-RUBYZIP-469156
- https://snyk.io/vuln/SNYK-RUBY-SINATRA-20488
- https://snyk.io/vuln/SNYK-RUBY-SINATRA-22027
- https://snyk.io/vuln/SNYK-RUBY-YARD-22004
- https://snyk.io/vuln/SNYK-RUBY-YARD-455636

Gemfile

@@ -2,30 +2,30 @@ source 'https://rubygems.org'
 
 ruby '2.1.2'
 
-gem "sinatra", '~> 1.4.6'
-gem "thin", '~> 1.6.4'
+gem "sinatra", "~> 2.0.2"
+gem "thin", "~> 1.7.0"
 gem "data_mapper", '~> 1.2.0'
 gem "dm-postgres-adapter", '~> 1.2.0'
-gem "ruby-saml", "~> 1.0.0"
+gem "ruby-saml", "~> 1.6.2"
 gem "chronic", '~> 0.10.2'
-gem "savon", '~> 2.11.1'
-gem "rubyzip", '~> 1.2.0'
-gem "nokogiri", '~> 1.6.7.2'
-gem "activesupport"
+gem "savon", "~> 2.11.1"
+gem "rubyzip", "~> 1.3.0"
+gem "nokogiri", "~> 1.11.0.0"
+gem "activesupport", ">= 5.2.4.3"
 gem "redis", '~> 3.3.0'
-gem "json", '~> 1.8.3'
-gem "rack_csrf", '~> 2.5.0'
-gem "rack-ssl", '~> 1.4.1'
+gem "json", "~> 2.3.0"
+gem "rack_csrf", "~> 2.5.0"
+gem "rack-ssl", "~> 1.4.1"
 gem "rufus-scheduler", '~> 3.2.0'
 gem 'pony', '~> 1.11'
 gem 'multipart-post', '~> 2.0.0'
 gem 'pg', '~> 0.18.4'
 gem 'rforce', '~> 0.13'
 gem 'xml-simple', '~> 1.1.5'
-gem 'httparty', '~> 0.13.7'
+gem 'httparty', '~> 0.14.0'
 gem "dotenv", '~> 2.1.1'
 gem 'rollbar', '~> 2.10.0'
-gem 'yard', '0.8.7.6'
+gem 'yard', '0.9.20'
 gem 'yard-dm', '0.1.1'
 gem 'yard-sinatra', '1.0.0'
 gem 'eventmachine', '1.0.7'