The lint command cannot parse a compressed chart with a pre-release
version, e.g. 0.1.0-alhpa: it errors out saying it cannot find the
Chart.yaml file. This is due to the way the lint command identifies the
chart dir name, i.e. using the last hyphen in the name of the compressed
file. Changing this method to using the name of the single directory
with the chart's name, as expected from decompressing a chart, allows
lint to parse pre-release charts.
Signed-off-by: Arash Deshmeh <adeshmeh@ca.ibm.com>