Python 3: Update python environment to use igwn-py39
Currently, the Gstreamer1.0/Python3 upgrade work is being done using the igwn-py38 conda environment.
When appropriate, we'd like to ensure that we can successfully run the pipeline using the newer igwn-py39 conda environment instead. Our end goal should be to port to Python3.10 when the a stable conda environment is released by IGWN.
Edited by Daniel Tang