Replace deprecated flag -intra for -g 1

See:
- https://gist.github.com/tayvano/6e2d456a9897f55025e25035478a3a50#file-gistfile1-txt-L67
- https://www.reddit.com/r/ffmpeg/comments/aeo1la/libx264_intra_option_information_please/

server/settings/publish_plugins.py

@@ -108,7 +108,7 @@ class TrayPublisherPublishPlugins(BaseSettingsModel):
               "output": [
                 "-pix_fmt yuv420p",
                 "-crf 18",
-                "-intra"
+                "-g 1",
               ]
             }
         }