fix: replace unsupported forceUTC option in tests

[vdistortion]

The current tests use the undocumented forceUTC option:

new Packer({ forceUTC: true })

However, the implementation only reads options.forceLocalTime:

entry.setTime(data.date, this.options.forceLocalTime)

and there is no runtime reference to forceUTC.

This PR replaces forceUTC: true with the equivalent supported option:

forceLocalTime: false

to align the tests with the actual public API.

[vdistortion]

This may also be related to a mismatch in archiver:
archiverjs/node-archiver#843