Add pre-release support

Description VS Code in release 1.63.0 added support for pre-releases and in the future they will be adding semver style tags. https://github.com/microsoft/vscode-docs/blob/vnext/release-notes/v1_63.md#publishing-pre-release-extensions

It would be a good idea IMO to allow for additional arguments to be passed into vsce, e.g. --pre-release. Of course care needs to be taken with how/when a pre-release build will be triggered. For example, the not so elegant solution that I thought of, is to have a separate .yml with --pre-release set as an argument that runs at every push on master and another .yml that triggers only on a GitHub release.

The important thing is to not allow for a normal release and a pre-release to publish under the exact same version number. There are some tricks that one can employ to ensure that but I would consider this responsibility lying with the developer of the VS Code extension and not this GitHub Action.

[HaaLeo]

Hi @cvergne the release you are referring to adds this option only to the api definitions this release does not change any functional behaviour of vsce.

If you package and publish your extension (dryRun: false) with this GitHub action the preRelease option is considered as one expects. However if you first package your extension with dryRun: true, preRelease: false and then in a second step publish the packaged extension with (extensionFile: 'path/To/extension.vsix', preRelease: true) the extension will not be published as pre-release. This is what I mean with

it seems that vsce only considers this option during the packaging step.

I hope this clarifies the behaviour of the preRelease flag.

[gnikit]

@kingdonb at the time I implemented this vsce had just added Pre-Release support on the VS Code Insiders build and ovsx had no support for Pre-release. Since the original contribution, ovsx has added the --pre-release flag when publishing.

It’s been on my TODO-list to open another PR to implement this, but I’ve haven’t gotten around to it yet.