Update prepare-credit.lua

Author: cthoyt

data/filters/prepare-credit.lua

@@ -71,6 +71,8 @@ local function prepare_credit (meta)
           degree = capitalize_first_letter(pandoc.utils.stringify(roleDict.degree))
           if invalidDegree(degree) then
             print("invalid degree for author " .. author.name .. ": " .. degree)
+            -- even though the degree is invalid, add the role anyway
+            table.insert(roleList, role)
           else
             table.insert(roleList, role .. " (" .. degree .. ")")
           end