Vararg-UnionAll deprecation error with Julia 1.7-DEV

[tomyun]

When using WriteVTK on Julia 1.7-DEV.501 with depwarn=error,

ERROR: LoadError: LoadError: Wrapping `Vararg` directly in UnionAll is deprecated (wrap the tuple instead).
Stacktrace:
  [1] UnionAll(v::TypeVar, t::Any)
    @ Core ./boot.jl:254
  [2] top-level scope
    @ ~/.julia/packages/WriteVTK/AMkQ9/src/gridtypes/structured/structured.jl:4
  [3] include(mod::Module, _path::String)
    @ Base ./Base.jl:386
  [4] include(x::String)
    @ WriteVTK ~/.julia/packages/WriteVTK/AMkQ9/src/WriteVTK.jl:1
  [5] top-level scope
    @ ~/.julia/packages/WriteVTK/AMkQ9/src/WriteVTK.jl:142
  [6] include
    @ ./Base.jl:386 [inlined]
  [7] include_package_for_output(pkg::Base.PkgId, input::String, depot_path::Vector{String}, dl_load_path::Vector{String}, load_path::Vector{String}, concrete_deps::Vector{Pair{Base.PkgId, UInt64}}, source::String)
    @ Base ./loading.jl:1209
  [8] top-level scope
    @ none:1
  [9] eval
    @ ./boot.jl:369 [inlined]
 [10] eval(x::Expr)
    @ Base.MainInclude ./client.jl:453
 [11] top-level scope
    @ none:1
in expression starting at /Users/runner/.julia/packages/WriteVTK/AMkQ9/src/gridtypes/structured/structured.jl:4
in expression starting at /Users/runner/.julia/packages/WriteVTK/AMkQ9/src/WriteVTK.jl:1

Here is the line indicated in the error.

https://github.com/jipolanco/WriteVTK.jl/blob/804ec53c8c176ddc093d31c5692c4bc9e491fc93/src/gridtypes/structured/structured.jl#L4

[jipolanco]

Thanks for the heads up.

I can't test right now locally on Julia master, so for now I'll wait. PRs are also welcome.