Update newton_trust_region.jl

Author: pkofod

src/multivariate/solvers/second_order/newton_trust_region.jl

@@ -312,7 +312,7 @@ mutable struct NewtonTrustRegionState{Tx,T,Tg,TH} <: AbstractOptimizerState
     f_x_previous::T
     s::Tx
     x_cache::Tx
-    g_cache::G
+    g_cache::Tg
     hard_case::Bool
     reached_subproblem_solution::Bool
     interior::Bool