gst-plugins-bad: add recommended orc dependency

GStreamer developers recommend to hard depend on orc even though it's an
optional dependency.

Closes #4225.

Signed-off-by: Dominyk Tiller <dominyktiller@gmail.com>

Formula/gst-plugins-bad.rb

@@ -1,6 +1,7 @@
 class GstPluginsBad < Formula
   desc "GStreamer plugins less supported, not fully tested"
   homepage "https://gstreamer.freedesktop.org/"
+  revision 1
 
   stable do
     url "https://gstreamer.freedesktop.org/src/gst-plugins-bad/gst-plugins-bad-1.8.3.tar.xz"
@@ -26,6 +27,7 @@ class GstPluginsBad < Formula
   depends_on "gst-plugins-base"
   depends_on "openssl"
 
+  depends_on "orc" => :recommended
   depends_on "dirac" => :optional
   depends_on "faac" => :optional
   depends_on "faad2" => :optional