Dockerfile: Update miniconda installer download location & remove unnecessary flag (#37082)
Summary:
https://repo.continuum.io/ was permanently moved to https://repo.anaconda.com
No need to specify -O since we have -o
Pull Request resolved: https://github.com/pytorch/pytorch/pull/37082
Differential Revision: D21182390
Pulled By: malfet
fbshipit-source-id: eeec70a883cbfd14105abd1ac6685f66afc02c02
