Added [compat] for POMDPPolicies 0.4 (#73)

Author: mossr

Diff for: Project.toml

@@ -22,7 +22,7 @@ Colors = "0.9, 0.10, 0.11, 0.12"
 D3Trees = "0.3"
 POMDPLinter = "0.1"
 POMDPModelTools = "0.3"
-POMDPPolicies = "0.3"
+POMDPPolicies = "0.3, 0.4"
 POMDPSimulators = "0.3"
 ProgressMeter = "1"
 POMDPs = "0.9"