SignTools failed without error details

[DamonYu6]

Squirrel version(s)
2.0.1

Description
In our CI environment, we occasionally notice that Squirrel fails when calling signtools for signing. However, since Squirrel doesn’t output the error messages from signtools, it’s difficult for us to troubleshoot the cause of the signing failure.

Steps to recreate
The signing failures occur occasionally and cannot be consistently reproduced

Expected behavior
Squirrel can output detailed error information when signing fails, which makes it easier for us to debug.

Actual behavior
Squirrel doesn't output detailed error information when signing fails.

Additional information
I’ve submitted a PR that will output all signtools information when signing fails, which will help us debug the reasons behind these failures.