6.1.1-4

What's Changed

• Enable videotoolbox, require MacOS >= 10.13 by @WyattBlue in #103
• Upgrade libass to 0.17.3 by @WyattBlue in #104
• Enable Window's media foundation by @WyattBlue in #105

Full Changelog: 6.1.1-3...6.1.1-4