Support PostGIS 3.6

[tordans]

PostGIS 3.6 was released on 2025/09/01 https://gitea.osgeo.org/postgis/postgis/src/branch/stable-3.6/NEWS

It would be great to have it available here as well.

[cvvergara]

Also for

• PostgreSQL 18.x
• pgRouting 4.0.0
• osm2pgRouting 3.0.0
• PostGIS 3.6.1

[sanak]

Thanks for the feedbacks!
I will try above in this weekend. 😊

[sanak]

@tordans (CC: @cvvergara)
It took a while due to my miss configuration in PR #75, but PostGIS 3.6 with PostgreSQL 18 Docker images were just shipped via PR #80.
https://hub.docker.com/r/pgrouting/pgrouting/tags?name=18