Update Dockerfile

[Gustav-Proxi]

This commit updates the Dockerfile to ensure compatibility with Detectron2 by upgrading the Python version from 3.6 to 3.8. The changes include: Base Image Change: Switched from nvidia/cuda:11.1.1-cudnn8-devel-ubuntu18.04 to nvidia/cuda:11.1.1-cudnn8-devel-ubuntu20.04 to provide a more recent environment with better package support. Python Installation: Removed the installation of Python 3.6 and replaced it with Python 3.8, ensuring that the python3 command points to the newly installed version.

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[Gustav-Proxi]

hey requesting to change accept this change to python 3.8

[captain357]

Thank you so much. I was trying to solve the same issue, but it was a hassle to figure out the dependency versions. And glady thought of looking at PR.

Few minor changes I had to do for my setup was:
installing pip required distutils which was not found
RUN apt-get -y install python3-distutils

adding -f flag to ln since the python3 binary was already existing
ln -fsv /usr/bin/python3.8 /usr/bin/python3

Again, thank you for help :)

[Gustav-Proxi]

glad to know it was of use to you, I'll include your recommendations and update the file so other are able to use it.