Spec: make spec the default rake task

Author: aramprice

.github/workflows/ruby.yml

@@ -11,4 +11,4 @@ jobs:
       - uses: ruby/setup-ruby@v1
         with:
           bundler-cache: true # runs 'bundle install' and caches installed gems automatically
-      - run: bundle exec rake spec
+      - run: bundle exec rake

Rakefile

@@ -14,4 +14,6 @@ import 'lib/tasks/publish/azure.rake'
 import 'lib/tasks/publish/gcp.rake'
 
 require 'rspec/core/rake_task'
-RSpec::Core::RakeTask.new(:spec)
+RSpec::Core::RakeTask.new(:spec)
+
+task default: [:spec]