hashFiles fails silently when it encounters a broken symlink

Describe the bug When the pattern passed to hashFiles() matches a broken symlink (a symlink that points to a non-existent file), hashFiles() silently fails and produces an empty hash. Example: https://github.com/formsort/formsort/runs/5096669434?check_suite_focus=true#step:4:139

To Reproduce Steps to reproduce the behavior:

1. Create a repo
2. Add a symlink to a non-existent file ln -s bla bla
3. Create a workflow that uses hashFiles("**") in it
4. Observe that the output of hashFiles("**") is empty witout any errors
5. Now enable step debug logging: https://docs.github.com/en/actions/monitoring-and-troubleshooting-workflows/enabling-debug-logging#enabling-step-debug-logging
6. Re-run the action
7. Observe the unhandled promise rejection error, silently being swallowed:

   ##[debug](node:1536) UnhandledPromiseRejectionWarning: Error: ENOENT: no such file or directory, stat '/home/runner/work/[redacted]'
   

Expected behavior hashFiles should either skip over broken symlinks or fail the whole job loudly, clearly indicating the error.

Runner Version and Platform

Version of your runner?

GitHub-hosted Ubuntu 20.04

Job Log Output

##[debug](node:1536) UnhandledPromiseRejectionWarning: Error: ENOENT: no such file or directory, stat '/home/runner/work/[redacted]'

[nikola-jokic]

Hi @BYK,

I reproduced the issue. Working on the fix so you don’t have to bother creating an example repository 😊.

[nikola-jokic]

Hi @BYK, don’t worry about it 😊. Your issue description was good enough! I submitted a PR fixing this issue