CI: Use 2.6.3 (ruby-grape#745)

Author: olleolleolle

.travis.yml

@@ -0,0 +1,34 @@
+language: ruby
+
+before_install:
+  - gem install bundler
+
+after_success:
+  - bundle exec danger
+
+rvm:
+  - 2.4.6
+  - 2.5.5
+  - 2.6.3
+env:
+  - MODEL_PARSER=grape-swagger-entity
+  - MODEL_PARSER=grape-swagger-representable
+  - GRAPE_VERSION=1.0.3
+  - GRAPE_VERSION=1.2.2
+  - GRAPE_VERSION=HEAD
+
+matrix:
+  fast_finish: true
+
+  include:
+    - rvm: 2.3.8
+      env:
+    - rvm: ruby-head
+      env:
+    - rvm: jruby-head
+      env:
+
+  allow_failures:
+    - rvm: 2.3.8
+    - rvm: ruby-head
+    - rvm: jruby-head