benchmarks/py-locust: Fix RUN_DEPENDS

- Use PY_TOMLI
- Bump PORTREVISION for dependency change

from pyproject.toml:
    "tomli>=1.1.0; python_version < '3.11'",

Reference:	https://github.com/locustio/locust/blob/2.37.10/pyproject.toml#L44
Approved by:	portmgr (blanket)
With hat:	python