feat(tool/charts): Check chart versions and update accordingly (#420)
feat(tool/charts): Check chart versions and update accordingly (#420)

When calling `tk tool charts vendor`, and a directory already exists at
the expected chart path, recursively delete that directory unless its
Chart.yaml matches the version of the chart specified in chartfile.yaml.

This allows vendored charts whose versions have changed to be downloaded
by tanka users without first removing the charts directory.

Return errors when Chart.yaml doesn't exist, or is malformed.

Signed-off-by: Craig Furman <cddc934d0056e6afacaae1df3d7a4bd01aad9e67@gmail.com>
grafana/tanka