title: Error "Unsatisfiable requirements detected for package Blink" in installation
body: <p>I am trying to install Blink and getting the following message.</p>
  
  <pre><code>(v1.0) pkg&gt; add Blink
    Updating registry at `~/.julia/registries/General`
    Updating git-repo `https://github.com/JuliaRegistries/General.git`
   Resolving package versions...
  ERROR: Unsatisfiable requirements detected for package Blink [ad839575]:
   Blink [ad839575] log:
   ├─possible versions are: [0.1.0-0.1.5, 0.2.0-0.2.1, 0.3.0-0.3.5, 0.4.0-0.4.4, 0.5.0-0.5.4, 0.6.0-0.6.2, 0.7.0, 0.8.0-0.8.1, 0.9.0] or uninstalled
   ├─restricted to versions * by an explicit requirement, leaving only versions [0.1.0-0.1.5, 0.2.0-0.2.1, 0.3.0-0.3.5, 0.4.0-0.4.4, 0.5.0-0.5.4, 0.6.0-0.6.2, 0.7.0, 0.8.0-0.8.1, 0.9.0]
   ├─restricted by julia compatibility requirements to versions: [0.7.0, 0.8.0-0.8.1, 0.9.0] or uninstalled, leaving only versions: [0.7.0, 0.8.0-0.8.1, 0.9.0]
   ├─restricted by compatibility requirements with HttpServer [58cfbd8c] to versions: [0.1.0-0.1.5, 0.8.0-0.8.1, 0.9.0] or uninstalled, leaving only versions: [0.8.0-0.8.1, 0.9.0]
   │ └─HttpServer [58cfbd8c] log:
   │   ├─possible versions are: [0.0.1-0.0.14, 0.1.0-0.1.7, 0.2.0, 0.3.0-0.3.1] or uninstalled
   │   └─restricted by julia compatibility requirements to versions: uninstalled
   └─restricted by compatibility requirements with WebSockets [104b5d7c] to versions: 0.1.0-0.1.5 or uninstalled — no versions left
     └─WebSockets [104b5d7c] log:
       ├─possible versions are: [0.0.1-0.0.6, 0.1.0-0.1.2, 0.2.0-0.2.3, 0.3.0, 0.4.0, 0.5.0, 1.0.0-1.0.3, 1.1.0-1.1.1, 1.2.0] or uninstalled
       ├─restricted by compatibility requirements with HTTP [cd3eb016] to versions: [0.0.1-0.0.6, 0.1.0-0.1.2, 0.2.0-0.2.3, 0.3.0, 0.4.0, 0.5.0] or uninstalled
       │ └─HTTP [cd3eb016] log:
       │   ├─possible versions are: [0.0.1-0.0.2, 0.4.0-0.4.3, 0.5.0, 0.5.2-0.5.5, 0.5.7, 0.6.0-0.6.14, 0.7.0-0.7.1, 0.8.0] or uninstalled
       │   └─restricted to versions 0.8.0 by an explicit requirement, leaving only versions 0.8.0
       └─restricted by julia compatibility requirements to versions: [1.0.0-1.0.3, 1.1.0-1.1.1, 1.2.0] or uninstalled, leaving only versions: uninstalled
  </code></pre>
  
  <p>I am not sure how to decipher, given the following packages installed.</p>
  
  <pre><code>(v1.0) pkg&gt; status
      Status `~/.julia/environments/v1.0/Project.toml`
    [c52e3926] Atom v0.7.6
    [336ed68f] CSV v0.4.3
    [a93c6f00] DataFrames v0.17.1
    [cd3eb016] HTTP v0.8.0
    [0862f596] HTTPClient v0.2.1
    [7073ff75] IJulia v1.16.0
    [682c06a0] JSON v0.20.0
    [e5e0dc1b] Juno v0.5.4
    [91a5bcdd] Plots v0.23.0
    [f3b207a7] StatsPlots v0.10.1
    [ddb6d928] YAML v0.3.2
    [ade2ca70] Dates
  </code></pre>
  
  <p>Do I need to install HTTPServer and Websockets packages?</p>
  
  <p>HTTP.jl version is v0.8.0 and it should meet requirement, no?</p>
  
  <pre><code>julia&gt; versioninfo()
  Julia Version 1.0.3
  Commit 099e826241 (2018-12-18 01:34 UTC)
  Platform Info:
    OS: Linux (x86_64-pc-linux-gnu)
    CPU: Intel(R) Core(TM) i5-2520M CPU @ 2.50GHz
    WORD_SIZE: 64
    LIBM: libopenlibm
    LLVM: libLLVM-6.0.0 (ORCJIT, sandybridge)
  Environment:
    JULIA_EDITOR = atom -a
    JULIA_NUM_THREADS = 2
  </code></pre>