fix: parse option error on elem is '-' or '--'

Signed-off-by: inhere <in.798@qq.com>

Author: inhere

src/Flags.php

@@ -21,6 +21,7 @@
 use function preg_match;
 use function str_split;
 use function stripos;
+use function strlen;
 use function strpos;
 use function substr;
 use function trim;
@@ -138,8 +139,8 @@ public static function parseArgv(array $params, array $config = []): array
                 continue;
             }
 
-            // is options
-            if ($p[0] === '-') {
+            // is options and not equals '-' '--'
+            if ($p[0] === '-' && '' !== trim($p, '-')) {
                 $value  = true;
                 $option = substr($p, 1);
                 $isLong = false;