benchmarks/py-locust-cloud: 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/locustcloud/locust-cloud/blob/1.26.3/pyproject.toml#L10
Approved by: portmgr (blanket)
With hat: python