This PR changes the three-column unique index to an on-insert trigger. This should fix the issues we're having with CI failures and still achieve the behavior of coalescing duplicate routes. I moved the concurrency_index calculation into an intermediate materialized view to separate the de-duplication capability from both DENSE_RANK() and from imposm updates.
transportation
Docs
Read the layer documentation at http://openmaptiles.org/schema#transportation

