added VCR Cassette to the 'generated' list so they get suppressed

lib/linguist/generated.rb

@@ -62,7 +62,8 @@ module Linguist
         generated_protocol_buffer? ||
         generated_jni_header? ||
         composer_lock? ||
-        node_modules?
+        node_modules? ||
+        vcr_cassette?
     end
 
     # Internal: Is the blob an XCode project file?
@@ -235,5 +236,13 @@ module Linguist
     def composer_lock?
       !!name.match(/composer.lock/)
     end
+
+    # Is the blob a VCR Cassette file?
+    #
+    # Returns true or false
+    def vcr_cassette?
+      # VCR Cassettes have "recorded_with: VCR" in the second last line.
+      return lines[-2].include?("recorded_with: VCR")
+    end
   end
 end