update vm_service_protos package to version 2

[jakemac53]

Update to vm_service_protos version ^2.0.0, this allows us to update protobuf from 3.1.0 -> 4.2.0 (this is only a transitive dep).

Should unlock the fix for #9534, although we still need a new version of vm_service_protos to be published which allows protobuf ^5.0.0 (we need 5.1.0 to get the default size increase).

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