Using local time as UTC in the scratch tracking file

[omus]

The now() function returns the current time in the system's local time zone. The code here adds the Z suffix which indicates UTC time:

https://github.com/JuliaPackaging/Scratch.jl/blob/df4d65620ea65816ba4c2f586d3d790db3dc99c6/src/Scratch.jl#L150

julia> using Dates

julia> @show now() now(UTC);
now() = DateTime("2022-07-13T09:56:50.017")
now(UTC) = DateTime("2022-07-13T14:56:50.018")