libcap2 vulnerability

USN-6166-1 fixed a vulnerability in libcap2. This update provides
the corresponding update for Ubuntu 14.04 ESM, Ubuntu 16.04 ESM
and Ubuntu 18.04 ESM.

Original advisory details:

Richard Weinberger discovered that libcap2 incorrectly handled certain long
input strings. An attacker could use this issue to cause libcap2 to crash,
resulting in a denial of service, or possibly execute arbitrary code.
(CVE-2023-2603)