feat(version): add --changelog-skip-unstable option

[Juveniel]

Description

Adds --changelog-skip-unstable option that allows to include changelogs from prereleases when publishing a stable release.

Motivation and Context

fixes: #3392, #3119, #2248

How Has This Been Tested?

Added unit and integration tests.

Types of changes

• New feature (non-breaking change which adds functionality)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.

[fahslaj]

We should not have duplicate prerelease headers in the generated markdown. Changes in prereleases should be aggregated together with the changes from the major release. See comment in lerna-publish-conventional-fixed-prerelease.spec.ts.

[fahslaj]

2.0.0-alpha.0 appears twice in this markdown file. This shouldn't happen, as users looking at version 2.0.0 won't care which specific prerelease version the feature was added in. Instead, we should get the changes from all the prereleases aggregated together with the changes from 2.0.0 itself, so it would look like this:

# [2.0.0](/compare/v1.0.0...v2.0.0) (YYYY-MM-DD)


### Features

* **package-1:** Add baz ([SHA](COMMIT_URL))
* **package-1:** Add foo ([SHA](COMMIT_URL))


# [2.0.0-alpha.0](/compare/v1.0.0...v2.0.0-alpha.0) (YYYY-MM-DD)


### Features

* **package-1:** Add foo ([SHA](COMMIT_URL))

[Juveniel]

@fahslaj I do agree that this is the expected markup.

conventional-changelog/conventional-changelog#675 suggests this is an issue with conventional-changelog. However, tests in this PR with independent versioning seem to be correct and the prerelease changes are properly aggregated see here. Any suggestions ?

[JamesHenry]

@Juveniel do you have plans to carry this forward please?

[Juveniel]

Hey @JamesHenry,

In order to continue with this PR, I need to first fix the issue in conventional-changelog. Unfortunately I am quite limited on time for the upcoming quarter and will not be able to do it asap.

In general, I would love for this feature to be pushed forward, as it really is a pain to not be able to aggregate changes from pre-release versions in the actual graduated version. I am even considering switching to nx release as a somewhat faster alternative once it goes out of beta, as the issue seems to be resolved with nx.