(MAINT) Drop Ruby 2.1.x and Puppet 4.x compatibility

Author: scotje

.travis.yml

@@ -16,18 +16,14 @@ script: 'SPEC_OPTS="--format documentation" COVERAGE="yes" bundle exec rake $CHE
 jobs:
   fast_finish: true
   include:
-    - rvm: 2.1.9
-      env: PUPPET_GEM_VERSION="~> 4" CHECK=spec
-    - rvm: 2.4.1
-      env: PUPPET_GEM_VERSION="~> 4" CHECK=spec
-    - rvm: 2.4.1
+    - rvm: 2.3
+      env: PUPPET_GEM_VERSION="~> 4" CHECK=rubocop
+    - rvm: 2.4
       env: PUPPET_GEM_VERSION="~> 5" CHECK=spec
     - rvm: 2.5
       env: PUPPET_GEM_VERSION="~> 6" CHECK=spec
     - rvm: 2.7
       env: PUPPET_GEM_VERSION="~> 6" CHECK=spec
-    - rvm: 2.1.9
-      env: PUPPET_GEM_VERSION="~> 4" CHECK=rubocop
     - bundler_args: ""
       rvm: 2.5
       before_script:

puppet-strings.gemspec

@@ -11,7 +11,7 @@ Gem::Specification.new do |s|
   s.email = 'info@puppet.com'
   s.homepage = 'https://github.com/puppetlabs/puppet-strings'
   s.description = s.summary
-  s.required_ruby_version = '>= 2.1.0'
+  s.required_ruby_version = '>= 2.3.0'
 
   s.extra_rdoc_files = [
     'CHANGELOG.md',
@@ -24,5 +24,5 @@ Gem::Specification.new do |s|
 
   s.add_runtime_dependency 'yard', '~> 0.9.5'
   s.add_runtime_dependency 'rgen'
-  s.requirements << 'puppet, >= 4.0.0'
+  s.requirements << 'puppet, >= 5.0.0'
 end