Support for --force flag in helm upgrade goal

[danparisi]

FEATURE REQUEST
Supporting --force flag when running helm upgrade

Currently it's not possible to add such flag during install / upgrade goal.
It'd be nice to have a configuration property to enable it.

Current upgrade command:

[INFO] installing the chart with install /home/jenkins/agent/workspace/service-directory/my-service
[DEBUG] Execute: /home/jenkins/agent/workspace/service-directory/target/helm/helm upgrade my-service /home/jenkins/agent/workspace/service-directory/my-service --install

Expected upgrade command:

[INFO] installing the chart with install /home/jenkins/agent/workspace/service-directory/my-service
[DEBUG] Execute: /home/jenkins/agent/workspace/service-directory/target/helm/helm upgrade my-service /home/jenkins/agent/workspace/service-directory/my-service --install **--force**

[danparisi]

Thanks for the very quick implementation