Missing changelog and GitHub release and Git tag for v3.0.0

[BenjaminBrienen]

https://www.npmjs.com/package/@vscode/test-electron

v3.0.0 was released recently, but it seems like some chores weren't done.

Changelog is not updated: https://github.com/microsoft/vscode-test/blob/main/CHANGELOG.md

One negative effect of this is dependabot gets confused: