feat(zsh): Finished reorganise zsh with a same entry point for all platforms

scripts/update.zsh

@@ -0,0 +1,40 @@
+# $DOTFILES/scripts/update.zsh
+# call by `update` alias defined in tools/zsh/alias.zsh
+# 使用别名 `update` 引用，别名定义于 tools/zsh/alias.zsh
+
+# Plugins #
+# Auto `git pull` on $ZDOTDIR/plugins
+for plugin in $ZDOTDIR/plugins/*; do
+  if [ -d "$plugin" ]; then
+    cd $plugin
+    git pull --quiet --no-edit
+  fi
+done
+
+# Update package managers #
+# Homebrew, macOS
+if command -v brew > /dev/null; then
+  brew update
+  brew upgrade
+fi
+
+# Arch
+if command -v pacman > /dev/null; then
+  sudo pacman -Syu
+fi
+
+# Debian
+if command -v apt > /dev/null; then
+  sudo apt update
+  sudo apt upgrade
+fi
+
+# Fedora
+if command -v dnf > /dev/null; then
+  sudo dnf update
+fi
+
+# WSL
+if command -v winget.exe > /dev/null; then
+  winget.exe upgrade
+fi