Trim the suffix from the binary on Windows

cmd/configure.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"os"
 	"path"
+	"strings"
 	"text/tabwriter"
 
 	"github.com/exercism/cli/config"
@@ -37,7 +38,7 @@ You can also override certain default settings to suit your preferences.
 		}
 		usrCfg.Normalize()
 		if usrCfg.Workspace == "" {
-			dirName := path.Base(BinaryName)
+			dirName := strings.Replace(path.Base(BinaryName), ".exe", "", 1)
 			defaultWorkspace := path.Join(usrCfg.Home, dirName)
 			_, err := os.Stat(defaultWorkspace)
 			// Sorry about the double negative.