[BE] Don't build CUDA-10.2 docker images (#87819)
As CUDA-10.2 should not longer be used in CI/CD
Test Plan: ` grep cuda10.2 .github -R|grep -v mock`
Pull Request resolved: https://github.com/pytorch/pytorch/pull/87819
Approved by: https://github.com/kit1980, https://github.com/ZainRizvi
