Update pyoncat conda
This MR update the environment file to use pyoncat from conda instead of pip.
During the maintenance period on Monday, 14 Oct 2024, all new projects will no longer create a container registry as part of the project area. Already existing projects will be unaffected at this time. Instead, users should utilize the official ORNL container registries at camden.ornl.gov (internal/moderate) and savannah.ornl.gov (external/low). Please see ORNL Today article for more info.
This MR update the environment file to use pyoncat from conda instead of pip.