Use python3 for the disttest environment
Use python3 for the disttest environment

Goodbye Python 2.

Change-Id: Icf5a9fc3c52ba94a864bc489ae1c7a06d858da58
Reviewed-on: https://gerrit.franz.com:9080/c/agraph-python/+/15969
Tested-by: Hudson <dfb64870173313a9a7b56f814c8e3b33e268497a@franz.com>
PTEST: Hudson <dfb64870173313a9a7b56f814c8e3b33e268497a@franz.com>
Reviewed-by: Ahmon Dancy <8f7d8ce2c6797410ae95fecd4c30801ee9f760ac@franz.com>

franzinc/agraph-python,franzinc/agraph-python,franzinc/agraph-python,franzinc/agraph-python