Setup a chart to use a library chart based on Helm 3 library charts

Following the guidance from Helm 3 library charts this repo represents a simple chart, mychart, that uses a library chart mylibchart which itself uses the common Helm helper chart as a dependency to acquire some common functions i.e. common.util.merge.

The list of repos added to the local client can be discovered by helm repo list. If it doesn't include incubator it will need to be added.

In order to use the external dependency of the common helper chart the incubator chart repository needs to be added to the repos accessible by the client. This is achieved via helm repo add incubator https://kubernetes-charts-incubator.storage.googleapis.com/

As changes are made to the local library chart the consuming chart needs to be instructed to update to the latest version. This is achieved via helm dependency update (within the root of the chart directory i.e. mychart)

Test the chart installation - helm install libdemo mychart/ --debug --dry-run. The configmap should include the value added in mychart (which have overridden the default, empty values set in mylibchart).

The chart can be installed in to a cluster if so wished but it is not necessary to provide the concept of library charts is working.