Enable WebSocket compression in .NET by default

.NET 6 added support for WebSocket compression to .NET: https://devblogs.microsoft.com/dotnet/announcing-net-6/#websocket-compression

Users can already enable that by themselves as it has been added as a property DangerousDeflate to the ClientWebSocketOptions which can be configured via the webSocketConfiguration of the GremlinClient constructor in Gremlin.Net.

Since we have enabled compression by default in Python and Java, it makes sense to also enable it by default in .NET. We can of course only do that for .NET 6 which is why we'll have to add that as an additional target framework to Gremlin.Net.

The .NET 6 announcement mentions that WebSocket compression together with encrypted content is susceptible to attacks like CRIME and BREACH that can reveal the encrypted content if an attacker is able to control data that is sent together with the encrypted content over the same WebSocket connection. That is why the property to enable compression is called DangerousDeflate and why compression can also be disabled on a per-message basis (source).

I suggest we can account for these possible attacks by disabling compression for the authentication messages we send to the server which contain credentials and by adding a note to the docs about this with a recommendation to disable compression if an application needs to send sensitive data, but also data controlled by (potentially untrusted) users to the server.
Since the attacker additionally needs to be able to monitor the network traffic between the client and the server, I guess >99% of applications are not affected by this and will therefore benefit from enabling compression by default.