fix typo in error log message

main.go

@@ -83,7 +83,7 @@ func downloadAddressList(url string) ([]string, error) {
 		line := scanner.Text()
 		_, ipnet, err := net.ParseCIDR(line)
 		if err != nil {
-			log.Printf("skippine line: failed to parse line '%s' to cidr: %v", line, err)
+			log.Printf("skipping line: failed to parse line '%s' to cidr: %v", line, err)
 			continue
 		}
 		v4Addresses = append(v4Addresses, ipnet.String())