1.4.0

• Add installation guide via Mint in #84

  For Mint package manager installation, run:

  $ mint install almazrafi/Fugen@1.4.0

• Generate text styles with using system font in #79

  New template option for text style generation - usingSystemFont:

  textStyles:
    file:
      key: ...
      includedNodes:
        - ...
    destination: ...
    templateOptions:
      usingSystemFonts: true

  This option generate text style with fonts SFProText and SFProDisplay using systemFont(ofSize:weight:) function.

• Added sort to image asset to avoid Content.json changes every run by @puchog in #90

• Xcode 13 support in #91