Describe the bug
The project is still using InstrumentKey based construction for it's TelemetryClient. The constructor has been removed in 3.x. As addressed in microsoft/ApplicationInsights-dotnet#2560

This affects:

• Sql4Cds/MarkMpn.Sql4Cds.SSMS/CommandBase.cs

  Line 31 in 82c97c8

  _ai = new TelemetryClient(new Microsoft.ApplicationInsights.Extensibility.TelemetryConfiguration("79761278-a908-4575-afbf-2f4d82560da6"));

• Sql4Cds/MarkMpn.Sql4Cds.XTB/PluginControl.cs

  Line 46 in 82c97c8

  _ai = new TelemetryClient(new Microsoft.ApplicationInsights.Extensibility.TelemetryConfiguration("79761278-a908-4575-afbf-2f4d82560da6"));

• Sql4Cds/MarkMpn.Sql4Cds.Engine/Ado/Sql4CdsConnection.cs

  Line 65 in 82c97c8

  _ai = new TelemetryClient(new Microsoft.ApplicationInsights.Extensibility.TelemetryConfiguration("79761278-a908-4575-afbf-2f4d82560da6"));

To Reproduce

1. Reference MarkMpn.Sql4Cds.Engine within a project using Microsoft.ApplicationInsights 3.x.
2. Create a concrete instance of CommandBase

Expected behaviour
The instance should be created.

Additional context
Using ConnectionString based construction for the client will be compatible with Application Insights 2.x and 3.x.

_ai = new TelemetryClient(new TelemetryConfiguration
{
    ConnectionString = "InstrumentationKey=79761278-a908-4575-afbf-2f4d82560da6"
});