Added Nextcloud Upload plugin (#1927)

Add plugin [Nextcloud Upload](https://github.com/Ellpeck/WoodpeckerPlugins/tree/main/nextcloud-upload) to the official plugin list.

there's already an official plugin that allows uploading
files using WebDAV, but my plugin has two Nextcloud-specific additions
that aren't part of the regular WebDAV spec:
- The ability to chunk uploads, which is necessary for larger files if
Nextcloud is hosted behind Cloudflare (which restricts uploads to a
maximum of 100MB)
- The ability to apply Nextcloud tags, which allows automatically
categorizing items and using Nextcloud's Retention plugin to easily
auto-remove older artifacts.

docs/plugins/woodpecker-plugins/plugins.json

@@ -123,6 +123,11 @@
       "name": "TODO-Checker",
       "docs": "https://codeberg.org/Epsilon_02/todo-checker/raw/branch/main/README.md",
       "verfied": false
+    },
+    {
+      "name": "Nextcloud Upload",
+      "docs": "https://raw.githubusercontent.com/Ellpeck/WoodpeckerPlugins/main/nextcloud-upload/README.md",
+      "verfied": false
     }
   ]
 }