In this article on sciencedirect.com epithelial skin cells are described as the products of epithelial multipotent stem cells and/or unipotent "progenitor" cells (which I presume is a way of describing a stem cell that only produces one type of cell - in this case an epithelialor skin cell). The epithelial multipotent stem cells can produce a variety of cells.
Most epithelial tissues self-renew throughout adult life due to the
presence of multipotent stem cells and/or unipotent progenitor cells [emphases mine].
Epithelial Stem Cells and Their Lineages Epithelial stem cells can generate tissues that display a fascinating array of cellular
architectures, each of which are specifically tailored for distinct
functions. In this review, we will focus on four well-characterized
epithelial stem cells whose tissues possess diverse architectural
designs and physiology: intestine, epidermis, mammary gland, and
So it seems the answer to my question is: both.