Refactor release workflows

[vinistock]

Motivation

This PR migrates our repo to use trusted publishing and make the release mechanisms more consistent. The changes are:

• Started using trusted publishing to release the gem and renamed the workflow to release_gem. To release, we need to push a tag matching v1.2.3 and that automatically creates the GH release
• Migrated the extension release action to also be based on tags, so that the way to release is consistent. The actual logic didn't change, just the triggers
  • Stable releases: push vscode-ruby-lsp-v1.2.3
  • Preview releases: push vscode-ruby-lsp-v1.2.3-preview

I also did two other things:

• Our automated version bump hasn't worked in a long time because Bundler keeps removing the Windows platform from the lockfile. If every PR requires manual intervention, then this automation is not actually helping much, so I just removed it
• Updated our NodeJS version to match what VS Code is using lately

[vinistock]

• Refactor release workflows #3911 👈 (View in Graphite)
• main

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