.travis.yml: Update supported Ruby versions (ruby-git#371)

perlun · web-flow · commit 27715e9ed79e · 2018-07-06T23:12:24.000+03:00
- Drop 1.9, 2.0 and 2.1 which are EOL
- Update 2.3, 2.4 and 2.5 specifiers (only specify minor version, not patch level)
- Update JRuby to use latest and greatest

Signed-off-by: Per Lundberg &lt;perlun@gmail.com&gt;
diff --git a/.travis.yml b/.travis.yml
@@ -1,15 +1,12 @@
 language: ruby
 rvm:
-  - 1.9.3
-  - 2.0.0
-  - 2.1.10
-  - 2.3.4
-  - 2.4.3
-  - 2.5.0
-  - jruby-9.1.15.0
+  - 2.3
+  - 2.4
+  - 2.5
+  - jruby
 matrix:
   allow_failures:
-  - rvm: jruby-9.1.15.0
+  - rvm: jruby
   fast_finish: true
 before_install:
   - gem install bundler
