tap-pin: Use CLI::Parser to parse args

Library/Homebrew/cmd/tap-pin.rb

@@ -2,10 +2,26 @@
 #:    Pin <tap>, prioritizing its formulae over core when formula names are supplied
 #:    by the user. See also `tap-unpin`.
 
+require "cli_parser"
+
 module Homebrew
   module_function
 
+  def tap_pin_args
+    Homebrew::CLI::Parser.new do
+      usage_banner <<~EOS
+        `tap-pin` <tap>
+
+        Pin <tap>, prioritizing its formulae over core when formula names are supplied
+        by the user. See also `tap-unpin`.
+      EOS
+      switch :debug
+    end
+  end
+
   def tap_pin
+    tap_pin_args.parse
+
     ARGV.named.each do |name|
       tap = Tap.fetch(name)
       raise "pinning #{tap} is not allowed" if tap.core_tap?