Update DebuggerProxy sources

[mkArtakMSFT]

This includes writing instructions for this, so next time I can handle it

[SteveSandersonMS]

@mkArtakMSFT I'm holding off on this until we confirm that we're updating to a specific version of Mono, since we should take the corresponding version of the debug proxy sources.

[mkArtakMSFT]

Thanks @SteveSandersonMS: #18478