future-private: add getPendingPositions request

src/Requests/GetPendingPositionsRequestContract.php

@@ -0,0 +1,17 @@
+<?php
+
+namespace Msr\LaravelBitunixApi\Requests;
+
+use Psr\Http\Message\ResponseInterface;
+
+interface GetPendingPositionsRequestContract
+{
+    /**
+     * Get pending positions
+     *
+     * @param string|null $symbol Trading pair (optional)
+     * @param string|null $positionId Position ID (optional)
+     * @return ResponseInterface
+     */
+    public function getPendingPositions(?string $symbol = null, ?string $positionId = null): ResponseInterface;
+}