Change ADD to COPY in Dockerfiles (#82151)
Docker docs says "For other items (files, directories) that do not require ADD’s tar auto-extraction capability, you should always use COPY": https://docs.docker.com/develop/develop-images/dockerfile_best-practices/#add-or-copy
I've found this by running https://github.com/hadolint/hadolint
This is a follow-up after https://github.com/pytorch/pytorch/pull/81944
Pull Request resolved: https://github.com/pytorch/pytorch/pull/82151
Approved by: https://github.com/huydhn, https://github.com/jeffdaily, https://github.com/ZainRizvi
