Upgrade rake to fix CVE-2020-8130

uk_planning_scraper.gemspec

@@ -21,7 +21,7 @@ Gem::Specification.new do |spec|
   spec.require_paths = ["lib"]
 
   spec.add_development_dependency "bundler", "~> 2.0"
-  spec.add_development_dependency "rake", "~> 10.0"
+  spec.add_development_dependency "rake", "~> 12.3.3"
   spec.add_development_dependency "rspec", "~> 3.8"
   spec.add_development_dependency "simplecov", "~> 0.16"
   spec.add_development_dependency "vcr", "~> 4.0"