Enable zst compression

src/Backup/Target/Compression/Factory.php

@@ -25,7 +25,8 @@ class Factory
         'gzip'  => 'Gzip',
         'bzip2' => 'Bzip2',
         'xz'    => 'Xz',
-        'zip'   => 'Zip'
+        'zip'   => 'Zip',
+        'zstd'   => 'Zstd'
     ];
 
     /**

src/Backup/Target/Compression/Zstd.php

@@ -0,0 +1,44 @@
+<?php
+namespace phpbu\App\Backup\Target\Compression;
+
+/**
+ * Zstd
+ *
+ * @package    phpbu
+ * @subpackage Backup
+ * @author     Sebastian Feldmann <[email protected]>
+ * @copyright  Sebastian Feldmann <[email protected]>
+ * @license    https://opensource.org/licenses/MIT The MIT License (MIT)
+ * @link       http://phpbu.de/
+ * @since      Class available since Release 3.2.1
+ */
+class Zstd extends Abstraction
+{
+    /**
+     * Command name
+     *
+     * @var string
+     */
+    protected $cmd = 'zstd';
+
+    /**
+     * Suffix for compressed files
+     *
+     * @var string
+     */
+    protected $suffix = 'zst';
+
+    /**
+     * MIME type for compressed files
+     *
+     * @var string
+     */
+    protected $mimeType = 'application/zstd';
+
+    /**
+     * Can this compression compress piped output
+     *
+     * @var bool
+     */
+    protected $pipeable = true;
+}

src/Cli/Executable/Tar.php

@@ -96,6 +96,7 @@ class Tar extends Abstraction implements Executable
         'bzip2',
         'gzip',
         'xz',
+        'zstd'
     ];
 
     /**