[iOS][CI] Update the dev cert (#45651)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/45651
### Summary
1. Update the iOS developer certificates. The new expiration date is 10/01/2021.
2. Restore the iOS arm64 jobs and the nightly.
### Test Plan
The following CI jobs succeed
- ci/circleci: pytorch_ios_11_2_1_arm64_build
- ci/circleci: pytorch_ios_11_2_1_arm64_custom_build
- ci/circleci: pytorch_ios_11_2_1_x86_64_build
Test Plan: Imported from OSS
Reviewed By: husthyc
Differential Revision: D24065648
Pulled By: xta0
fbshipit-source-id: 758f41de8296fdfbd3cfad87e9445c2acafd5f94
