.travis.yml in in_threads-1.4.0 vs .travis.yml in in_threads-1.5.0

@@ -3,23 +3,25 @@
 rvm:
   - '1.8.7-p371'
   - '1.9.3-p551'
   - '2.0.0-p648'
   - '2.1.10'
-  - '2.2.6'
-  - '2.3.3'
-  - '2.4.0'
+  - '2.2.8'
+  - '2.3.5'
+  - '2.4.2'
   - 'ruby-head'
-  - 'jruby-1.7.26'
   - 'jruby-9.0.5.0'
-  - 'jruby-9.1.5.0'
+  - 'jruby-9.1.9.0'
+before_install:
+  - gem update --system
+  - gem update bundler
 script: bundle exec rspec
 matrix:
   include:
     - env: RUBOCOP=✓
-      rvm: '2.4.0'
+      rvm: '2.4.2'
       script: bundle exec rubocop
     - env: CHECK_RUBIES=✓
-      rvm: '2.4.0'
+      rvm: '2.4.2'
       script: bundle exec travis_check_rubies
   allow_failures:
     - rvm: 'ruby-head'