Can't install deb package on systems with a headless jre

[theHilikus]

Expected behavior

Installation of deb package succeeds since java is present in the system

Actual behavior

$ sudo apt install mqtt-cli

The following packages have unmet dependencies:
 mqtt-cli : Depends: default-jre but it is not installable or
                     java8-runtime but it is not installable

To Reproduce

Steps

• Install a headless package like openjdk-8-jre-headless
• Try to install mqtt

Details

• Affected MQTT CLI version(s): 4.7.3
• Used JVM version: openjdk-8-jre-headless 8u292-b10-0ubuntu1~16.04.1

[theHilikus]

It seems to me the change is trivial so I went ahead and did the PR #271

This is the only occurrence I could find of the string java8-runtime