build(deps-dev): bump yard from 0.9.19 to 0.9.20

Bumps [yard](https://github.com/lsegal/yard) from 0.9.19 to 0.9.20.
- [Release notes](https://github.com/lsegal/yard/releases)
- [Changelog](https://github.com/lsegal/yard/blob/master/CHANGELOG.md)
- [Commits](lsegal/yard@v0.9.19...v0.9.20)

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

Gemfile

@@ -21,7 +21,7 @@ end
 
 group :development, :test do
   gem 'pry', '~> 0.10'
-  gem 'yard', '~> 0.8'
+  gem 'yard', '~> 0.9'
   gem 'rubocop', '~> 0.28'
 end
 

Gemfile.lock

@@ -149,7 +149,7 @@ GEM
     websocket-client-simple (0.3.0)
       event_emitter
       websocket
-    yard (0.9.19)
+    yard (0.9.20)
 
 PLATFORMS
   ruby
@@ -173,7 +173,7 @@ DEPENDENCIES
   sysexits (~> 1.2)
   twitter (> 5.15)
   webmock (~> 3.3)
-  yard (~> 0.8)
+  yard (~> 0.9)
 
 BUNDLED WITH
    2.0.1