Add and fix exhaustive

.golangci.yaml

@@ -43,7 +43,6 @@ linters:
     - forbidigo
     - dupl
     - goconst
-    - exhaustive
     - varnamelen
 
     # We might want to enable this, but it might be a lot of work

cmd/headscale/headscale.go

@@ -23,6 +23,8 @@ func main() {
 		colors = true
 	case termcolor.LevelBasic:
 		colors = true
+	case termcolor.LevelNone:
+		colors = false
 	default:
 		// no color, return text as is.
 		colors = false