Install Krypton via Homebrew instead of separate step

Was getting an "unsupported OS" error (kryptco/kr#308)

But it seems like it's possible to install this via Homebrew so I'm gonna go with that (see kryptco/kr#308 (comment))

Brewfile

@@ -3,6 +3,7 @@ tap "homebrew/cask"
 tap "homebrew/cask-drivers"
 tap "homebrew/cask-versions"
 tap "homebrew/core"
+tap "kryptco/tap"
 brew "awscli"
 brew "mackup"
 brew "mas"
@@ -13,6 +14,7 @@ brew "ruby-build"
 brew "rbenv"
 brew "yarn"
 brew "zsh-git-prompt"
+brew "kryptco/tap/kr", link: false
 cask "1password"
 cask "authy"
 cask "bartender"

README.md

@@ -85,10 +85,9 @@ Restore app settings from mackup
 % mackup restore
 ```
 
-## Kryptonite (SSH / GPG Keys)
+## Krypton (SSH / GPG Keys)
 
 ```zsh
-% curl https://krypt.co/kr | sh
 % kr pair
 % kr codesign
 ```