[CT-3198] Automate a --dry-run of changelog generation

[emmyoop]

We want to be able to automate changelog generation to notify internal staff of what an upcoming release is going to include. Automation will decrease friction of this step instead of manually running it for every release.

Inputs:
version(required): 1.8.0
prerelease (optional): rc1
branch (required, default to main?): 1.6.latest
repository (required): dbt-core

It needs to handle the following release types
rc1 (special because it needs to include previous beta changelogs along with the new changes)

• changie batch <version> --include <version> --prerelease <prerelease value> --dry-run
  pre-releases
• changie batch <version> --prerelease <prerelease value> --dry-run
  final releases with a prerelease
• changie batch <version> --include <version> --dry-run
  patches (final release without a prerelease)
• changie batch <version> --dry-run

Output the changelog somewhere clear.

• Send to slack channel?
• Send to notification in workflow
• Send to file