feat/add-back-matrix-test-domain
main
We use pub.solar as our server_name and matrix.pub.solar:8448 for matrix federation traffic. The well-known record served at https://pub.solar/.well-known/matrix/server should point to matrix.pub.solar:8448. The same is true for test.pub.solar and matrix.test.pub.solar:8448. https://matrix-org.github.io/synapse/latest/delegate.html
This caused nix version 2.13 being using in the devshell instead of recent version 2.18, which we use by default in PubSolarOS