Dep/failure on v1.7

[ChrisRackauckas]

ERROR: LoadError: Wrapping `Vararg` directly in UnionAll is deprecated (wrap the tuple instead).
Stacktrace:
  [1] UnionAll(v::TypeVar, t::Any)
    @ Core .\boot.jl:255
  [2] top-level scope
    @ C:\Users\accou\.julia\packages\ChainRulesCore\bxKCw\src\projection.jl:134
  [3] include(mod::Module, _path::String)
    @ Base .\Base.jl:417
  [4] include(x::String)
    @ ChainRulesCore C:\Users\accou\.julia\packages\ChainRulesCore\bxKCw\src\ChainRulesCore.jl:1
  [5] top-level scope
    @ C:\Users\accou\.julia\packages\ChainRulesCore\bxKCw\src\ChainRulesCore.jl:31
  [6] include
    @ .\Base.jl:417 [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:1318
  [8] top-level scope
    @ none:1
  [9] eval
    @ .\boot.jl:373 [inlined]
 [10] eval(x::Expr)
    @ Base.MainInclude .\client.jl:453
 [11] top-level scope
    @ none:1
in expression starting at C:\Users\accou\.julia\packages\ChainRulesCore\bxKCw\src\projection.jl:134
in expression starting at C:\Users\accou\.julia\packages\ChainRulesCore\bxKCw\src\ChainRulesCore.jl:1
ERROR: LoadError: Failed to precompile ChainRulesCore [d360d2e6-b24c-11e9-a2a3-2a2ae2dbcce4] to C:\Users\accou\.julia\compiled\v1.7\ChainRulesCore\jl_BEA4.tmp.

pointing to const _PZ_Tuple = Tuple{_PZ,Vararg{<:_PZ}} # 1 or more ProjectTo{<:AbstractZeros}

[oxinabox]

why do deprecations break precompilation?

Should be an easy fix though

[oxinabox]

For my reference this was introduced in
JuliaLang/julia#38136