fix update

Dockerfile

@@ -7,7 +7,7 @@ FROM python:3.9-slim
 
 # Copy just the requirements into the working directory so it gets cached by itself
 COPY ./requirements.txt /code/requirements.txt
-RUN apt-get install ffmpeg
+RUN apt-get update && apt-get install -y ffmpeg
 
 # Install the dependencies from the requirements file
 RUN pip install --no-cache-dir --upgrade -r /code/requirements.txt