Output Video written to Input Directory (Premade Docker Image)

When running the [premade image on Docker Hub](https://hub.docker.com/r/eulertour/manim/tags/), it creates the mp4 output video file in the tmp/input directory instead of tmp/output. The video is exposed from the container, however it is placed in the INPUT_PATH directory rather than OUTPUT_PATH. The file path listed in the logs is correct.

The log from running the docker-compose image is:
```
Media will be written to /tmp/output/. You can change this behavior with the --media_dir flag.

File ready at /tmp/input/videos/example_scenes/480p15/SquareToCircle.mp4

Played 3 animations
```