Update debugger to 1.12.3 (#1648)
Update debugger to 1.12.3 (#1648)

This updates the debugger to the 1.12.3 version. At the same time this switches to the new VS CDN for the debugger. Lastly, this changes the package version to beta 3.
OmniSharp/omnisharp-vscode,gregg-miskelly/omnisharp-vscode,gregg-miskelly/omnisharp-vscode,OmniSharp/omnisharp-vscode,gregg-miskelly/omnisharp-vscode,gregg-miskelly/omnisharp-vscode,OmniSharp/omnisharp-vscode,OmniSharp/omnisharp-vscode,OmniSharp/omnisharp-vscode