Add video demo to README.

Author: davabase

README.md

@@ -4,6 +4,8 @@ A real-time speech to text transcription app built with Flet and OpenAI Whisper.
 
 ![Screenshot](screenshot.png)
 
+https://user-images.githubusercontent.com/69365652/205431746-1ece6d20-85a6-4112-ba5a-ee050b67268c.mp4
+
 ## Setting Up An Environment
 On Windows:
 ```
@@ -70,4 +72,4 @@ Read more about Whisper here: https://github.com/openai/whisper
 
 Read more about Flet here: https://flet.dev/
 
-The code in this repository is public domain.
+The code in this repository is public domain.