Prepare a script to make GitHub release packages

[arrowtype]

From Dave at undercasetype#186 (comment):

I'd like to request the build script build 9 static families as follows for 162 styles, based on the 3 x 3 x 9 x 2 combinations implied by this graphic on the minisite, and include a Fraunces-v1_000-static.zip build artifact that includes them, alongside a Fraunces-v1_000-variable.zip build artifact.

Tasks:

• make script to generate static & variable woff2 files
• make script to generate variable subsets + CSS (adapt from Tilt)
• document usage in readme
• (along with issue Prepare Fraunces for Google Fonts #1) add a way for fonts to be versioned on build/release

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OTFs

• check into copyright: INFO:ufo2ft.outlineCompiler:The copyright was normalized for storage in the CFF table and consequently some characters were dropped: 'Copyright 2020 The Fraunces Project Authors github.comundercasetypeFraunces'

The copyright string on the name table is fine:

  <name>
    <namerecord nameID="0" platformID="3" platEncID="1" langID="0x409">
      Copyright 2020 The Fraunces Project Authors (github.com/undercasetype/Fraunces)
    </namerecord>
    <namerecord nameID="1" platformID="3" platEncID="1" langID="0x409">
      Fraunces 9pt
    </namerecord>
    <namerecord nameID="2" platformID="3" platEncID="1" langID="0x409">
      Bold Italic
    </namerecord>
    <namerecord nameID="3" platformID="3" platEncID="1" langID="0x409">
      1.000;UCT;Fraunces9pt-BoldItalic
    </namerecord>
    <namerecord nameID="4" platformID="3" platEncID="1" langID="0x409">
      Fraunces 9pt Bold Italic
    </namerecord>
    <namerecord nameID="5" platformID="3" platEncID="1" langID="0x409">
      Version 1.000;[f813b42e0]
    </namerecord>
    <namerecord nameID="6" platformID="3" platEncID="1" langID="0x409">
      Fraunces9pt-BoldItalic
    </namerecord>
    <namerecord nameID="13" platformID="3" platEncID="1" langID="0x409">
      This Font Software is licensed under the SIL Open Font License, Version 1.1. This license is available with a FAQ at: https://scripts.sil.org/OFL
    </namerecord>
    <namerecord nameID="14" platformID="3" platEncID="1" langID="0x409">
      https://scripts.sil.org/OFL
    </namerecord>
    <namerecord nameID="18" platformID="3" platEncID="1" langID="0x409">
      Fraunces 9pt Bold Italic
    </namerecord>
    <namerecord nameID="25" platformID="3" platEncID="1" langID="0x409">
      FrauncesItalic
    </namerecord>
  </name>

[arrowtype]

This is closed with https://github.com/arrowtype/Fraunces/tree/da0f8f53300387793db90f121785527d62dfa199/mastering