Coordinates of VariableInfo inconsistent #412
Description
The coordinates attribute of the esmvalcore.cmor.table.VariableInfo class is a dictionary with for CMIP6 tables coordinate axis as keys and for CMIP5 tables coordinate names as keys. This is inconsistent and confusing.
This issue was reported by @bascrezee in ESMValGroup/ESMValTool#1338 (comment)