fix: expires can be a Date, string, or number

[jspri]

Brought types inline with documentation for getSignedUrl and getSignedPolicy

https://cloud.google.com/nodejs/docs/reference/storage/2.3.x/File#getSignedUrl

The documentation states options.expires can be any type.

Internally new Date() accepts string | number | Date so I have used that.

https://github.com/Microsoft/TypeScript/blob/c2898db9dd58c9b0681d6131ed6076d71d89e6b5/lib/lib.es2015.core.d.ts#L90

You may want to update the web documentation from any to string | number | Date but I'm not sure of your conventions for that.

• Tests and linter pass
• Code coverage does not decrease (if any source code was changed)
• Appropriate docs were updated (if necessary)

[jspri]

lint

[JustinBeckwith]

Thank you so much for the fix!