Adds Rakefile task to package and run the same in Github Actions.

This change introduces a new target in the Rakefile for building a tar.gz of the code. This tar can then be uploaded to Github Actions.

Author: vrr-21

.github/workflows/ruby.yml

@@ -36,5 +36,5 @@ jobs:
       run: bundle exec rake package
     - uses: actions/upload-artifact@v2
       with:
-        name: 'aws-codedeploy-agent-tar'
+        name: 'aws-codedeploy-agent.tar.gz'
         path: 'pkg/aws-codedeploy-agent-1.3.2.tar.gz'