Upgrade ShellCheck to v0.7.2 (#56445)
Summary:
[First ShellCheck release in over a year!](https://github.com/koalaman/shellcheck/releases/tag/v0.7.2) I'm thankful for doing https://github.com/pytorch/pytorch/issues/55109 at the beginning of this month, because otherwise `master` would have just suddenly started failing a few hours ago.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/56445
Test Plan:
CI. You can also run `shellcheck` locally; for instance, if you're on Mac and [installed it with Homebrew](https://github.com/koalaman/shellcheck/tree/v0.7.2#installing):
```sh
brew upgrade shellcheck
rm -r .extracted_scripts ; tools/extract_scripts.py --out=.extracted_scripts
tools/run_shellcheck.sh .jenkins/pytorch .extracted_scripts
```
Reviewed By: janeyx99
Differential Revision: D27874084
Pulled By: samestep
fbshipit-source-id: 3bd871a368fe03aecd559e2f55bce36af49cfa27
