Deprecation warning when precompiling PlotlyJS.jl

[IljaK91]

Describe the bug

I get a deprecation warning when precompiling PlotlyJS

┌ Warning: `@get!(dict, key, default)` at C:\Users\Ilja\.julia\packages\WebIO\nTMDV\src\scope.jl:160 is deprecated, use `get!(()->default, dict, key)` instead.
└ @ Base deprecated.jl:204
┌ Warning: `@get!(dict, key, default)` at C:\Users\Ilja\.julia\packages\WebIO\nTMDV\src\scope.jl:357 is deprecated, use `get!(()->default, dict, key)` instead.
└ @ Base deprecated.jl:204
WARNING: using HTTP.stack in module Mux conflicts with an existing identifier.

Version info

julia> versioninfo()
Julia Version 1.5.1
Commit 697e782ab8 (2020-08-25 20:08 UTC)
Platform Info:
  OS: Windows (x86_64-w64-mingw32)
  CPU: Intel(R) Core(TM) i5-5200U CPU @ 2.20GHz
  WORD_SIZE: 64
  LIBM: libopenlibm
  LLVM: libLLVM-9.0.1 (ORCJIT, broadwell)
Environment:
  JULIA_EDITOR = "C:\Users\Ilja\AppData\Local\Programs\Microsoft VS Code\Code.exe"
  JULIA_NUM_THREADS = 4

Status `C:\Users\Ilja\.julia\environments\v1.5\Project.toml`
  [70b36510] AutomaticDocstrings v1.0.1
  [6e4b80f9] BenchmarkTools v0.5.0
  [336ed68f] CSV v0.7.7
  [5d742f6a] CSVFiles v1.0.0
  [1375f997] CompEcon v0.4.0
  [8f4d0f93] Conda v1.4.1
  [a93c6f00] DataFrames v0.21.7
  [31a5f54b] Debugger v0.6.5
  [31c24e10] Distributions v0.23.8
  [634d3b9d] DrWatson v1.15.1
  [d872a56f] ElectronDisplay v1.0.0
  [442a2c76] FastGaussQuadrature v0.4.2
  [f6369f11] ForwardDiff v0.10.12
  [38e38edf] GLM v1.3.10
  [28b8d3ca] GR v0.51.0
  [c91e804a] Gadfly v1.3.0
  [19dc6840] HCubature v1.4.0
  [7073ff75] IJulia v1.21.3
  [a98d9a8b] Interpolations v0.12.10
  [aa1ae85d] JuliaInterpreter v0.7.26
  [b964fa9f] LaTeXStrings v1.1.0
  [2774e3e8] NLsolve v4.4.1
  [47be7bcc] ORCA v0.5.0
  [429524aa] Optim v0.22.0
  [9b87118b] PackageCompiler v1.2.1
  [d96e819e] Parameters v0.12.1
  [f0f68f2c] PlotlyJS v0.14.0
  [91a5bcdd] Plots v1.6.0
  [438e738f] PyCall v1.91.4
  [d330b81b] PyPlot v2.9.0
  [1fd47b50] QuadGK v2.4.1
  [fcd29c91] QuantEcon v0.16.2
  [1a8c2f83] Query v1.0.0
  [295af30f] Revise v2.7.3
  [f2b01f46] Roots v1.0.5
  [efcf1570] Setfield v0.7.0
  [90137ffa] StaticArrays v0.12.4
  [2913bbd2] StatsBase v0.33.0
  [4c63d2b9] StatsFuns v0.9.5
  [3eaba693] StatsModels v0.6.13
  [f3b207a7] StatsPlots v0.14.11
  [e88e6eb3] Zygote v0.5.5
  [c4c688b2] jlpkg v1.2.1
  [37e2e46d] LinearAlgebra
  [9a3f8284] Random
  [10745b16] Statistics
  [8dfed614] Test

[sglyon]

HI @IljaK91

This warning appears to come from within WebIO.jl, but has recently been fixed on master: JuliaGizmos/WebIO.jl@aadf220

Once they release a new version of that package, we'll update our dependencies and the warning will go away.