Created by: heavengate

运行PPYOLO遇到slice找不到kernel报错的可先用此方法规避

报错如下：

Error: op slice does not have kernel for data_type[float]:data_layout[ANY_LAYOUT]:place[CUDAPinnedPlace]:library_type[PLAIN] at (/paddle/paddle/fluid/framework/operator.cc:1090)
[operator < slice > error]

最近Paddle develop分支有修改，每日版本跑PPYOLO会报上述错误，可以先在ppdet/modeling/loss/yolo_loss.py的130行添加规避，如本PR中修改方式，Paddle develop问题我们在确认

targets = [target * 1.0 for target in targets]