Deprecate Mackup in my setup

Since macOS 14 (Sonoma), Mackup has been broken 😞

See here:
- lra/mackup#1924
- https://www.reddit.com/r/macapps/comments/1f1j41a/avoid_mackup_if_you_are_runing_sonoma_or_later/

There are some workarounds but I am taking this opportunity to just simplify my setup a bit

Most of my settings are not that precious that I rely on Mackup to perfectly replicate between machines; I can just do some manual configuration and get most of the way there

I'm removing references to Mackup and its configuration from this repo in this commit

.vscode/tasks.json

@@ -9,13 +9,6 @@
       "group": "build",
       "type": "shell",
       "command": "brew bundle dump -f"
-    },
-    {
-      "label": "Mackup Backup",
-      "detail": "Backup settings with Mackup",
-      "group": "build",
-      "type": "shell",
-      "command": "mackup backup"
     }
   ]
 }

Brewfile

@@ -32,11 +32,9 @@ brew "hivemind"
 brew "jasper"
 brew "shared-mime-info"
 brew "libheif"
-brew "libffi"
-brew "python@3.9"
 brew "libraw"
 brew "imagemagick"
-brew "mackup"
+brew "libffi"
 brew "mas"
 brew "nginx"
 brew "node"
@@ -47,6 +45,7 @@ brew "postgresql@12"
 brew "pyenv"
 brew "python@3.10"
 brew "python@3.11"
+brew "python@3.9"
 brew "qt"
 brew "ruby-build"
 brew "rbenv"

README.md

@@ -13,7 +13,6 @@ Do the following, in this order:
 1. [Sign into iCloud](#icloud)
 1. [Sign into Fastmail](#fastmail)
 1. [Install Mac App Store apps](#mac-app-store)
-1. [Restore Mackup](#mackup)
 1. [Set up SSH](#ssh)
 1. [Set up Node](#node)
 
@@ -51,7 +50,7 @@ Install Homebrew
 /bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install.sh)"
 ```
 
-Get `brew` in the PATH for now (this gets resolved for real when Mackup restores my .zshrc below)
+Get `brew` in the PATH for now:
 
 ```zsh
 eval "$(/opt/homebrew/bin/brew shellenv)"
@@ -158,28 +157,6 @@ After setting up 1Password and iCloud above, run the Homebrew install step again
 cd ~/code/dotfiles && brew bundle # The `mas` steps should complete now that we're signed into iCloud
 ```
 
-## Mackup
-
-Restore app settings from mackup
-
-Copy the configuration to the home directory because I don't use the default
-
-```zsh
-cp ~/code/dotfiles/mackup/.mackup.cfg ~/
-```
-
-Copy the custom config directory for custom apps
-
-```zsh
-cp -r ~/code/dotfiles/mackup/.mackup ~/.mackup
-```
-
-Restore all the settings
-
-```zsh
-mackup restore
-```
-
 ## SSH
 
 Enable the 1Password [SSH Agent](https://developer.1password.com/docs/ssh/agent/):