Fix the version mapping doc when using master
Ensure we are using the chart-version passed into our manage_version script, rather than the version in the local file. (Which will always be latest in master, instead of the version we are actually trying to document)
Thanks @PhilippeVienne for pointing the issue out to us in !947 (closed)
(Also updates version_mappings.md
to correct values)
Edited by Jason Plum