build: add ubuntu bionic to circleci
build: add ubuntu bionic to circleci

This is done to avoid breaking the compatibility with it.

Signed-off-by: Lorenzo Fontana <0189fb5ac8a393aa741cf57f29cfe3228fcad081@gmail.com>

draios/falco,draios/falco,draios/falco,draios/falco,draios/falco,draios/falco,draios/falco,draios/falco