Fix `define_derived_metadata` so that it supports cascades.
Created by: myronmarston
For example:
RSpec.configure do |c|
c.define_derived_metadata(:elasticsearch) do |meta|
meta[:vcr] = true
end
c.define_derived_metadata(:vcr) do |meta|
meta[:retries] = 2
end
end
With this configuration, an example or group tagged with :elasticsearch
should get tagged with :vcr
as well, which in turn should add
retries: 2
metadata to the example or group. Before this change,
this did not work properly, because we did look to see if additional
metadata blocks should apply after applying them once.