Update Go.ignore to add Delve compiled output

[dvelitchkov]

Add Go Delve debugger compiled output. Default is "./ __debug_bin" per https://github.com/go-delve/delve/blob/master/Documentation/usage/dlv_debug.md#options

Reasons for making this change:

The Go Delve debugger is the de-facto standard Go debugger. Add its default compiled binary to the ignore list.

Links to documentation supporting these rule changes:

https://github.com/go-delve/delve/blob/master/Documentation/usage/dlv_debug.md#options

[jollyrogue]

Is there a way to bump this? I'd like this added too.

[daniellanner]

+1 I add __debug_bin to every go .gitignore.