replaced usage of generated_quantities with returned

Author: torfjelde

test/ext/DynamicPPLMCMCChainsExt.jl

@@ -3,7 +3,7 @@
     model = demo()
 
     chain = MCMCChains.Chains(randn(1000, 2, 1), [:x, :y], Dict(:internals => [:y]))
-    chain_generated = @test_nowarn generated_quantities(model, chain)
+    chain_generated = @test_nowarn returned(model, chain)
     @test size(chain_generated) == (1000, 1)
     @test mean(chain_generated) ≈ 0 atol = 0.1
 end