feat: added COPY --from to enable builder pattern

Author: gplanchat

src/Dockerfile/CopyFrom.php

@@ -0,0 +1,20 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Kiboko\Component\Dockerfile\Dockerfile;
+
+final readonly class CopyFrom implements LayerInterface, \Stringable
+{
+    public function __construct(
+        private string $sourcePath,
+        private string $destinationPath,
+        private string $from,
+    ) {
+    }
+
+    public function __toString(): string
+    {
+        return sprintf('COPY --from=%s %s %s', $this->from, $this->sourcePath, $this->destinationPath);
+    }
+}