Travis: use jruby-9.2.8.0, add Ruby 2.4.6, 2.5.5, 2.6.3 (#881)

.travis.yml

@@ -1,6 +1,5 @@
 language: ruby
 dist: trusty
-sudo: false
 group: beta
 cache: bundler
 
@@ -11,10 +10,11 @@ branches:
   only: [master]
 
 rvm:
-  - 2.2.9
-  - 2.3.6
-  - 2.4.3
-  - 2.5.0
+  - 2.2.10
+  - 2.3.8
+  - 2.4.6
+  - 2.5.5
+  - 2.6.3
 
 env:
   - RAILS_VERSION=4
@@ -37,9 +37,9 @@ matrix:
       env: RAILS_VERSION=4
     - rvm: jruby-1.7.27
       env: JRUBY_OPTS="--dev" RAILS_VERSION=4
-    - rvm: jruby-9.2.0.0
+    - rvm: jruby-9.2.8.0
       env: JRUBY_OPTS="--dev -J-Djruby.launch.inproc=true -J-Xmx1024M" RAILS_VERSION=4
-    - rvm: jruby-9.2.0.0
+    - rvm: jruby-9.2.8.0
       env: JRUBY_OPTS="--dev -J-Djruby.launch.inproc=true -J-Xmx1024M" RAILS_VERSION=5
     - rvm: ruby-head
       env: RAILS_VERSION=0