etcd vulnerabilities

USN-5628-1 fixed vulnerabilities in etcd.
This update provides the corresponding updates for Ubuntu 18.04 ESM.

Original advisory details:

It was discovered that etcd incorrectly handled certain specially crafted
WAL files. An attacker could possibly use this issue to cause a denial of
service. (CVE-2020-15106, CVE-2020-15112)

It was discovered that etcd incorrectly handled directory permissions when
trying to create a directory that exists already. An attacker could
possibly use this issue to obtain sensitive information. (CVE-2020-15113)

It was discovered that etcd incorrectly handled endpoint setup. An
attacker could possibly use this issue to cause a denial of
service. (CVE-2020-15114)