update picodet tutorial trainign configuration

tutorials/train/object_detection/picodet.py

@@ -44,16 +44,16 @@ model = pdx.det.PicoDet(num_classes=num_classes, backbone='ESNet_l')
 # API说明：https://github.com/PaddlePaddle/PaddleX/blob/develop/docs/apis/models/detection.md
 # 各参数介绍与调整说明：https://github.com/PaddlePaddle/PaddleX/blob/develop/docs/parameters.md
 model.train(
-    num_epochs=40,
+    num_epochs=20,
     train_dataset=train_dataset,
     train_batch_size=14,
     eval_dataset=eval_dataset,
     pretrain_weights='COCO',
     learning_rate=.05,
-    warmup_steps=30,
-    warmup_start_lr=0.0,
-    save_interval_epochs=2,
-    lr_decay_epochs=[8, 13],
+    warmup_steps=24,
+    warmup_start_lr=0.005,
+    save_interval_epochs=1,
+    lr_decay_epochs=[6, 8, 11],
     use_ema=True,
     save_dir='output/picodet_esnet_l',
     use_vdl=True)