Bump rake from 10.5.0 to 12.3.3 (#61)

Bumps [rake](https://github.com/ruby/rake) from 10.5.0 to 12.3.3.
- [Release notes](https://github.com/ruby/rake/releases)
- [Changelog](https://github.com/ruby/rake/blob/master/History.rdoc)
- [Commits](ruby/rake@v10.5.0...v12.3.3)

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

Gemfile

@@ -8,7 +8,7 @@ gem 'bundler', '~> 1.16'
 gem 'haml'
 
 group :development, :test do
-  gem 'rake', '~> 10.0'
+  gem 'rake', '~> 12.3'
   gem 'rspec', '~> 3.0'
   gem 'rspec_junit_formatter'
   gem 'rubocop'

Gemfile.lock

@@ -18,7 +18,7 @@ GEM
       ast (~> 2.4.0)
     powerpack (0.1.1)
     rainbow (3.0.0)
-    rake (10.5.0)
+    rake (12.3.3)
     rspec (3.7.0)
       rspec-core (~> 3.7.0)
       rspec-expectations (~> 3.7.0)
@@ -60,7 +60,7 @@ DEPENDENCIES
   bundler (~> 1.16)
   commonmarker
   haml
-  rake (~> 10.0)
+  rake (~> 12.3)
   rspec (~> 3.0)
   rspec_junit_formatter
   rubocop