Is it possible to create a virtual environment using CUDA?

First, is there any particular reason you’re stuck using Julia v1.2? That’s several years old at this point and basically unsupported - the current long-term support version is v1.6. Using an old version of Julia also prevents you from using modern versions of Julia’s CUDA stack - I’d highly recommend upgrading to at least Julia v1.6.

Julia’s built-in package manager supports environments by default, so you shouldn’t need any external package. Briefly:

julia> cd(mktempdir())

(@v1.8) pkg> activate CUDATestProject # enter Pkg mode with the ] key
  Activating new project at `C:\Users\alexa\AppData\Local\Temp\jl_gcrbSw\CUDATestProject`

(CUDATestProject) pkg> add CUDA
    Updating registry at `C:\Users\alexa\.julia\registries\General.toml`
   Resolving package versions...
   Installed GPUArraysCore ─ v0.1.0
[...]

julia> using CUDA

julia> @time sum(CUDA.rand(10^8)) # CUDA is downloaded at time of first use
  Downloaded artifact: CUDA
145.488497 seconds (30.93 M allocations: 2.484 GiB, 0.50% gc time, 4.94% compilation time)
5.000604f7

julia> @time sum(CUDA.rand(10^8))
  0.093087 seconds (145 allocations: 7.844 KiB)
4.9994404f7