ahh, ok, until we can get a newer version of Tidier released, you may have to uninstall Tidier and install the individual packages you need.
You can also try
using Pkg; Pkg.add(url = "https://github.com/TidierOrg/TidierDB.jl")
or use an old version of tidierdb which does not have extensions so you would have use ODBC to create your own connection, and then
set_sql_mode(:mssql)
and then use tidierdb like that.