🚸 Add pull/upgrade command

[shnizzedy]

Fixes

Fixes #8 by @shnizzedy

Description

Introduces a pull command with an upgrade alias that will pull a given container with the same top-level options as run and utils so users can upgrade images without having to use an interface other than cpac

Checklist

• My pull request has a descriptive title (not a vague title like Update index.md).
• My pull request targets the develop branch of the repository.
• My commit messages follow best practices.
• My code follows the established code style of the repository.
• I added tests for the changes I made (if applicable).
• I updated the changelog.
• I added or updated documentation (if applicable).
• I tried running the project locally and verified that there are no
  visible errors.

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