Add fork banner to README

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README.md

@@ -10,6 +10,8 @@ YoutubeDL-Material is a Material Design frontend for [youtube-dl](https://rg3.gi
 
 Now with [Docker](#Docker) support!
 
+> **Note**: This is a fork of [Tzahi12345/YoutubeDL-Material](https://github.com/Tzahi12345/YoutubeDL-Material). For the original project, please visit the upstream repository.
+
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 ## Getting Started