ci: Add cu102 to CI and packaging, remove cu100 (#1980)

* ci: Add cu102 to CI and packaging

Adds cu102 to our testing matrix as well as change the default manywheel
version to be cu102.

Also adds a function to get manylinux images instead of it being a
conditional block.

Signed-off-by: Eli Uriegas <[email protected]>

* .circleci: Remove cu100, no longer built

We removed the build for cu100 in upstream pytorch as well since we have
begun to support cu102

Signed-off-by: Eli Uriegas <[email protected]>

* Fix lint

* More lint fixes

Co-authored-by: Francisco Massa <[email protected]>

Author: seemethere