Add chart dimension metadata: multipleRequired

[iosonosempreio]

Add the property multipleRequired to chart dimensions that require more than a single data-header input to work (e.g. Steps in Alluvial Diagram).

{
    id: 'steps',
    name: 'steps',
    validTypes: ['number', 'date', 'string'],
    required: true,
    multiple: true,

    multipleRequired: true

  }

[bianchimro]

hi @iosonosempreio, this should already do the trick (minValues property):

{
    id: 'steps',
    name: 'steps',
    validTypes: ['number', 'date', 'string'],
    required: true,
    multiple: true,
    minValues: 2
  }

(there is also another maxValues prop)