Grafana- Update Dependency Helm Charts That are Out of Date (and update Doc with Missing Step)

Grafana DEVELOPMENT_MAINTENANCE.md instructions for updating Grafana package doesn't include the helm dependency update ./chart step like some of our other packages we maintain, as a result the grafana/chart/charts/gluon-0.4.10.tgz hasn't updated from 0.4.10 to current 0.5.0.

We need to 1) update the outdated dependency, 2) increment the version tag, and 3) add in the helm dependency update ./chart to the doc so that the developer will update the package dependency.