Add copyparty to Web-based File Managers (#3552)

Co-authored-by: nodiscc <nodiscc@gmail.com>

README.md

@@ -965,6 +965,7 @@ Web-based [file managers](https://en.wikipedia.org/wiki/File_manager).
 _Related: [Groupware](#groupware)_
 
 - [Apaxy](https://oupala.github.io/apaxy/) - Theme built to enhance the experience of browsing web directories, using the mod_autoindex Apache module and some CSS to override the default style of a directory listing. ([Source Code](https://github.com/oupala/apaxy)) `GPL-3.0` `HTML`
+- [copyparty](https://github.com/9001/copyparty) - Portable file server with accelerated resumable uploads, deduplication, WebDAV, FTP, zeroconf, media indexer, video thumbnails, audio transcoding, and write-only folders, in a single file with no mandatory dependencies. ([Demo](https://a.ocv.me/pub/demo/)) `MIT` `Python`
 - [DirectoryLister](https://www.directorylister.com/) - Simple PHP based directory lister that lists a directory and all its sub-directories and allows you to navigate there within. ([Source Code](https://github.com/DirectoryLister/DirectoryLister)) `MIT` `PHP`
 - [filebrowser](https://filebrowser.org/) - Web File Browser with a Material Design web interface. ([Source Code](https://github.com/filebrowser/filebrowser)) `Apache-2.0` `Go`
 - [FileGator](https://filegator.io/) - FileGator is a powerful multi-user file manager with a single page front-end. ([Demo](https://demo.filegator.io), [Source Code](https://github.com/filegator/filegator)) `MIT` `PHP`