CopyItemsd transform saves data into same key

[Nic-Ma]

Describe the bug
This line of CopyItemsd seems not correct:
https://github.com/Project-MONAI/MONAI/blob/dev/monai/transforms/utility/dictionary.py#L740
It saves all the data of keys into the same new_key.

[Nic-Ma]

Hi @rijobro ,

I checked the git history, this PR caused the issue: #1676.
We should use:

for key, new_key in zip(self.keys * self.times, self.names)

Let me create a fix PR for your review.

Thanks.

[rijobro]

Hi @Nic-Ma , good spot, thanks!