Improve Auto-detection of crates in workspace

[t-moe]

I've tried the auto-detection of packages in a workspace (by leaving the packages empty in knope.toml) and noticed a few missing features:

• Changelog files are not detected. Could we maybe add support for detecting them if they have the standard name CHANGELOG.md ?
• Cargo.toml of dependent Packages is not added to versioned_files if the dependency is renamed.
  e.g. i have two crates, prefix_main and prefix_sub, where prefix_main has a dependency sub={package="prefix_sub", ..} which is not picked up / not updated by knope.

Thank you for creating + improving Knope!