USN-8733-2: Gzip vulnerabilities

USN-8733-1 fixed vulnerabilities in Gzip. This update provides the corresponding fix for Gzip on Ubuntu 14.04 LTS, Ubuntu 18.04 LTS and Ubuntu 20.04 LTS. Original advisory details: Michał Majchrowicz and Marcin Wyczechowski discovered that Gzip's gzexe utility created temporary files in an insecure manner when mktemp was unavailable.