(maint) update Gemfile to allow use of non-vulnerable rake version 12.3.3

Author: DavidS

Gemfile

@@ -7,11 +7,12 @@ gemspec
 
 group :tests do
   gem 'codecov'
-  gem 'rake', '~> 10.0'
   gem 'rspec', '~> 3.0'
   # rubocop 0.58 throws when testing against ruby 2.1, so pin to the latest,
   # unless we're dealing with jruby...
   if RUBY_PLATFORM == 'java'
+    # load a rake version that works on java
+    gem 'rake', '~> 10.0'
     # load a rubocop version that works on java for the Rakefile
     gem 'parser', '2.3.3.1'
     gem 'rubocop', '0.41.2'
@@ -23,6 +24,8 @@ group :tests do
     gem 'parallel', '1.13.0'
     gem 'rubocop-rspec'
   else
+    # the rake everyone else should be using
+    gem 'rake', '~> 12.3'
     # 2.1-compatible analysis was dropped after version 0.58
     # This needs to be removed once we drop puppet4 support.
     gem 'rubocop', '~> 0.57.0'