You can update your python version to 3.8 in conda using the command
conda install -c anaconda python=3.8
as per https://anaconda.org/anaconda/python. Though not all packages support 3.8 yet, running
conda update --all
may resolve some dependency failures. You can also create a new environment called py38 using this command
conda create -n py38 python=3.8
Edit – note that the conda install option will potentially take a while to solve the environment, and if you try to abort this midway through you will lose your Python installation (usually this means it will resort to non-conda pre-installed system Python installation).