Breaking change introduced

[rsdmike]

In PR #406

app-functions-sdk-go/internal/webserver/server.go

Line 350 in e8b2565

addr = fmt.Sprintf("%v:%d", webserver.Config.Service.Host, webserver.Config.Service.Port)

is NOT backwards compatible with the SDK and actually against best practices per golang documentation https://golang.org/pkg/net/#Listen.

The address can use a host name, but this is not recommended, because it will create a listener for at most one of the host's IP addresses

This is different behavior introduced from the introduction of the app-functions-sdk-go to the current release:

It should be:

app-functions-sdk-go/internal/webserver/server.go

Line 234 in 52cf5f6

p := fmt.Sprintf(":%d", webserver.Config.Service.Port)

[lenny-goodell]

Agree that defaulting it to Host when setting is blank breaks backwards compatibility for the App Services. Don't agree it would always be blank. It should use what ever the new setting values is and by default that will be blank if the setting isn't in the config.

Having it be blank by default circumvents the Kong proxy only access for snaps. Proper non-breaking fix is this only without check for blank and defaulting to Host value and setting that value to localhost in the ASC config TOML files. @rsdmike , agree?

	addr := fmt.Sprintf("%v:%d", webserver.Config.Service.ServerBindAddr, webserver.Config.Service.Port)

[charles-knox-intel]

I think @lenny-intel's code snippet allows for proper backwards compatibility and still allows for users to set ServerBindAddr. I will make a PR with the change.