Convert DSC and DSC Lite modules to use changelog generator

Convert the DSC the DSC Lite to use changelog generator

Fully automated changelog generation - This gem generates a changelog file based on tags, issues and merged pull requests (and splits them into separate lists according to labels) from GitHub Issue Tracker.

Since you don't have to fill your CHANGELOG.md manually now: just run the script.

add the following code into .sync.yml file

optional:

    ':development':

      - gem: 'github_changelog_generator'

        git: 'https://github.com/skywinder/github-changelog-generator'

        ref: '20ee04ba1234e9e83eb2ffb5056e23d641c7a018'

        condition: "Gem::Version.new(RUBY_VERSION.dup) >= Gem::Version.new('2.2.2')"

Also ensure any references to the Rakefile being managed are removed from the .sync.yml:

# The rakefile is heavily modified for the build process

Rakefile:

  unmanaged: true 

• run pdk update
• bundle install --path .bundle/gems/
• CHANGELOG_GITHUB_TOKEN=token
• Move existing changelog to HISTORY.md
• bundle exec rake changelog