Update rake requirement from ~> 10.0 to ~> 12.3

Updates the requirements on [rake](https://github.com/ruby/rake) to permit the latest version.
- [Release notes](https://github.com/ruby/rake/releases)
- [Changelog](https://github.com/ruby/rake/blob/master/History.rdoc)
- [Commits](ruby/rake@v12.3.0...v12.3.3)

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

Gemfile.lock

@@ -57,7 +57,7 @@ GEM
     pathutil (0.16.1)
       forwardable-extended (~> 2.6)
     public_suffix (3.0.1)
-    rake (12.3.0)
+    rake (12.3.3)
     rb-fsevent (0.10.2)
     rb-inotify (0.9.10)
       ffi (>= 0.5.0, < 2)

jekyll-display-medium-posts.gemspec

@@ -17,7 +17,7 @@ Gem::Specification.new do |spec|
 
 
   spec.add_development_dependency "bundler", "~> 1.12"
-  spec.add_development_dependency "rake", "~> 10.0"
+  spec.add_development_dependency "rake", "~> 12.3"
   spec.add_development_dependency "rspec", "~> 0"
 
 end