Remove support for unsupported versions of Ruby

.travis.yml

@@ -4,37 +4,10 @@ before_install:
   - gem install bundler
   - unset _JAVA_OPTIONS
 rvm:
-  - 1.9.3
-  - 2.0.0
-  - 2.1.10
-  - 2.2.10
-  - 2.3.8
-  - 2.4.5
-  - 2.5.3
-  - jruby-9.1.9.0
-matrix:
-  exclude:
-    # activesupport 5 only supports ruby 2.2.2 and later
-    - gemfile: gemfiles/activesupport5.0.gemfile
-      rvm: 1.9.3
-    - gemfile: gemfiles/activesupport5.1.gemfile
-      rvm: 1.9.3
-    - gemfile: gemfiles/activesupport5.2.gemfile
-      rvm: 1.9.3
-
-    - gemfile: gemfiles/activesupport5.0.gemfile
-      rvm: 2.0.0
-    - gemfile: gemfiles/activesupport5.1.gemfile
-      rvm: 2.0.0
-    - gemfile: gemfiles/activesupport5.2.gemfile
-      rvm: 2.0.0
-
-    - gemfile: gemfiles/activesupport5.0.gemfile
-      rvm: 2.1.10
-    - gemfile: gemfiles/activesupport5.1.gemfile
-      rvm: 2.1.10
-    - gemfile: gemfiles/activesupport5.2.gemfile
-      rvm: 2.1.10
+  - 2.4.6
+  - 2.5.5
+  - 2.6.3
+  - jruby-9.2.6.0
 
 gemfile:
   - gemfiles/activesupport4.1.gemfile

CHANGELOG.md

@@ -1,5 +1,7 @@
 ### develop
 
+* Removes support for versions of Ruby which are no longer supported by the Ruby project.
+
 ### 0.11.0 / April 23, 2019
 
 * Add support for mapping Range objects to cron range syntax [Tim Craft](https://github.com/javan/whenever/pull/725)