Maint: upgrade golibs and env error wrapping

internal/configuration/surfshark.go

@@ -1,6 +1,8 @@
 package configuration
 
 import (
+	"fmt"
+
 	"github.com/qdm12/gluetun/internal/constants"
 )
 
@@ -31,12 +33,12 @@ func (settings *Provider) readSurfshark(r reader) (err error) {
 
 	settings.ServerSelection.Regions, err = r.env.CSVInside("REGION", constants.SurfsharkRegionChoices())
 	if err != nil {
-		return err
+		return fmt.Errorf("environment variable REGION: %w", err)
 	}
 
 	settings.ServerSelection.Hostnames, err = r.env.CSVInside("SERVER_HOSTNAME", constants.SurfsharkHostnameChoices())
 	if err != nil {
-		return err
+		return fmt.Errorf("environment variable SERVER_HOSTNAME: %w", err)
 	}
 
 	return nil