libptouch の更新に追従

ruby/libptouch.gemspec

@@ -13,6 +13,7 @@ Gem::Specification.new do |spec|
   spec.summary = "FFI bindings for libptouch (Brother P-touch USB raster printing)"
   spec.description = [
     "Ruby wrapper around the ptouch_label C library libptouch.",
+    "Supports PT-P900W, PT-P750W, PT-P710BT and related open_usb_vid_pid / --pid.",
     "Requires libptouch shared library (libusb, libpng)."
   ].join(" ")
   spec.license = "MIT"