version bump - 0.12.0

[houllette]

v0.12.0

• Removed
  • Support for minimum Elixir version 1.4 (POTENTIALLY BREAKING - only applies if you relied on Elixir 1.4, 1.5+ is still supported)
• Enhancements
  • Adds support for HEEx to XSS.Raw
  • Adds --version CLI flag
  • README Improvements
    • Umbrella App usage
    • Clearer installation process
    • Layout changes
  • Updated dependencies
• Bug fixes
  • Adds to_string() to exit_on
  • Sets SSL opt verify_peer in version check
  • Reworks -v, --verbose printing to not use the now deprecated Macro.to_string/2
• Misc
  • Allows atom values for threshold in config file
  • Uses SPDX ID for licenses in mixfile
  • Fixed typo