Cleans up travis (#740)

- updates Gemfile

.travis.yml

@@ -3,21 +3,18 @@ language: ruby
 sudo: false
 
 before_install:
-  - gem update --system
   - gem install bundler
 
 after_success:
-  # - coveralls
   - bundle exec danger
 
 rvm:
   - 2.4.5
   - 2.5.3
-  - 2.6.0
+  - 2.6.1
 env:
   - MODEL_PARSER=grape-swagger-entity
   - MODEL_PARSER=grape-swagger-representable
-  - GRAPE_VERSION=0.19.2
   - GRAPE_VERSION=1.0.3
   - GRAPE_VERSION=1.2.2
   - GRAPE_VERSION=HEAD

Gemfile

@@ -25,13 +25,8 @@ group :development, :test do
   gem 'rack-test'
   gem 'rake'
   gem 'rdoc'
-  gem 'rspec', '~> 3.0'
-  # TODO: change back after 2.6.0 release and updated rubocop version
-  if RUBY_VERSION == '2.6.0'
-    gem 'rubocop', git: 'https://github.com/rubocop-hq/rubocop.git', require: false
-  else
-    gem 'rubocop', '~> 0.61', require: false
-  end
+  gem 'rspec', '~> 3.8'
+  gem 'rubocop', '~> 0.63', require: false
 end
 
 group :test do