Create a Package

If you keep the same license, then just add your name to it. Say it was this original license https://github.com/mauro3/Parameters.jl/blob/master/LICENSE.md, then change it to something like:

Copyright (c): Mauro Werder (2015-2018), Han Hasse (2019)

If it is not the same type of license (or no license, or no open source license), then it’s more tricky.

the problem is the outdated package is not mine

Yes, but if it has an open source license you can use the code, subject to the license.

same error,
could you tell me where the problem is?

have you checked https://lectures.quantecon.org/jl/testing.html

Page not found…
I guess it is moved here:
https://julia.quantecon.org/more_julia/testing.html