Update to GTFS Schedule Validator v7.1

[evansiroky]

User story / feature request

As a transit data quality analyst,
I want to use the most up-to-date GTFS Schedule Validator (currently v5.0),
So that I can have the latest validation results

Acceptance Criteria

Data pipeline is updated to use GTFS Schedule Validator v7.1. No backfill needed.

Notes

MobilityData discussion: MobilityData/gtfs-validator#2011

Previous update to our pipeline: #3305