v1.7.0: 🛍 Purchase Command

• ✨ New purchase command for purchasing free apps #264 (resolves #2, #145)
  thanks, @blochberger!
• 🐟 Seriously more interactive fish completions #242
  thanks, @lwolfsonkin!
• ⬆️ Nimble (8.0.9) #274
• 🛠 Xcode 11.5 #273
• 🧹 Purchase cleanup #272
• ♻️ SoftwareMap Protocol #271
• 🕊 Swift 5 #255
  • ⚒️ Xcode 10.2 and macOS 10.14 required to build
• ⬆️ Commandant (0.17.0) #255
• ⬆️ Nimble (8.0.4) #255
• ⬆️ Quick (2.2.0) #255
• ➖ Result #255
• 💡 Update readme with simpler tap usage #241