Changes proposed in this PR:

Bump to version 0.2.0 and add changelog

How I've tested this PR:

Invoked several commands on the hcp cli and verified the version.

How I expect reviewers to test this PR:

Check changelog format looks good.

Checklist:

• Tests added if applicable
• CHANGELOG entry added or label 'pr/no-changelog' added to PR

  Run CHANGELOG_PR=<PR number> make changelog/new-entry for guidance
  in authoring a changelog entry, and commit the resulting file, which should
  have a name matching your PR number. Entries should use imperative present
  tense (e.g. Add support for...)