gtad.yaml: Update to the released GTAD 0.6
gtad.yaml: Update to the released GTAD 0.6

variant types now use comma (,) as a delimiter instead of | (because regexes).
Also: moved around the `schema` section to be closer to `$ref`.

QMatrixClient/libqmatrixclient,QMatrixClient/libqmatrixclient,Fxrh/libqmatrixclient