`citation` field can be removed from method metadata

[bl-young]

From “description”, remove “\nSource citation: Bare 2021” since the “source” Ref below already provides this

https://github.com/USEPA/LCIAformatter/blob/b16f092a4ec4f23b56dabe6bfac86fa8a55fee71/lciafmt/data/description.yaml#L8

h/t @a-w-beck