We should include the version information in two ways:

1. Make the archive unzip all the files into a directory with the right name. For example, timezonedb-2017b.zip, when unpacked, should create a directory timezonedb-2017b/ and should place all of the unzipped files inside this directory.
2. The archive should include a file version.txt with the version string. For example, we should produce a file timezonedb-2017b/version.txt which has all relevant version information.