WP Staging Pro 5.7.1

* Fix: On some servers, autoloader tries to load Composer\InstalledVersions although this doesn't exist. We fix this by only loading classes that exist

* Fix: Certain default plugins like wps-hide are not excluded anymore during cloning #1742
* Fix: Scheduled backup not always executed #1754
* Fix: Backup folder is deleted during backup restore on Windows OS #1737
* Fix: On backup restore retry deleting an item again in next request instead of re adding it at the end of queue, if item isn't completely deleted in current request #1758
* Enh: Refactor normalizePath() #1751
* Enh: Optimize table selection to reduce POST characters. Send either selected tables or excluded tables whichever is smaller along to reduce the POST size for cloning and pushing #1727
* Enh: Allow automatic update of WP STAGING | PRO on the staging site. It can still be disabled using the filter wpstg.notices.disable.plugin-update-notice #1749
* Enh: Add filter wpstg.backup.restore.extended-search-replace. The extended search replace allow properly replacing to destination URL for some plugins like rev-sliders #1741

* Fix: If there is a damaged backup in backup folder, automated backup does not work any longer #1707
* Fix: Support UNC paths like //servername/path Unix or \\servername\path DOS/Windows #1698
* Fix: Remove prefixed vendor namespace from the Normalizer class in the idn-intl polyfill #1720
* Fix: Handle SSL related errors and catch other exceptions while making remote request to refresh Google token #1718
* Fix: Backup does not restore theme if theme does not have a style.css #1719
* Fix: Missing exception in Backup Extractor.php #1724
* Enh: List damaged backup files in the UI and mark them #1710
* Enh: Remove message "backup metadata not found" in debug log #1710
* Enh: Clean up debug messages #1722
* Enh: Add missing escaping of POST output #1705