Fix NGA-Subduction logic tree

subduction/interface/gmm-tree.json

• need to use the BASIN flavor of AG20 (AG_20_CASCADIA_ADJ_INTERFACE_BASIN instead of AG_20_CASCADIA_ADJ_INTERFACE)
• AM09/Zhao06 weights are currently 50/50 (0.125/0.125) - hasn't AM09 been down-weighted to 1/3-2/3 (0.08/0.17)?

subduction/slab/gmm-tree.json

• Confirm AG20 un-adjusted and adjusted weights, currently 0.0825/0.1675 (not quite 1/3-2/3, which would be 0.0833/0.1667)

changed milestone to %Beta release of CONUS NSHM

Resolved in !85 (merged)

closed