add best pendulum_ddpg_linearnoise

Author: kengz

rl/spec/classic_experiment_specs.json

@@ -934,8 +934,8 @@
       "batch_size": 64,
       "n_epoch": 1,
       "tau": 0.005,
-      "lr": 0.001,
-      "critic_lr": 0.001,
+      "lr": 0.0001,
+      "critic_lr": 0.005,
       "exploration_anneal_episodes": 50,
       "gamma": 0.97,
       "hidden_layers": [400, 300],