Update CI tests and packaging for ignite v0.4.7

[Nic-Ma]

Is your feature request related to a problem? Please describe.
Currently, we always set the minimal ignite requirements to 0.4.4:
https://github.com/Project-MONAI/MONAI/blob/dev/monai/config/deviceconfig.py#L256
And set CI tests and packaging to the latest ignite version for compatible tests and verify / leverage the latest features.
Congratulations @vfdev-5 for the v0.4.7 release of ignite:
https://github.com/pytorch/ignite/tree/v0.4.7
I will try to update our dependency ASAP.