gitignore: Also ignore subproject symlinks

These subproject dirs are only ignored if they are directories if you
use a trailing slash.

.gitignore

@@ -19,37 +19,37 @@ gstreamer-vaapi
 libnice
 __pycache__
 meson/
-subprojects/gst-integration-testsuites/
+subprojects/gst-integration-testsuites
-subprojects/gst-devtools/
+subprojects/gst-devtools
-subprojects/gst-editing-services/
+subprojects/gst-editing-services
-subprojects/gst-libav/
+subprojects/gst-libav
-subprojects/gst-omx/
+subprojects/gst-omx
-subprojects/gst-plugins-bad/
+subprojects/gst-plugins-bad
-subprojects/gst-plugins-base/
+subprojects/gst-plugins-base
-subprojects/gst-plugins-good/
+subprojects/gst-plugins-good
-subprojects/gst-plugins-ugly/
+subprojects/gst-plugins-ugly
-subprojects/gst-python/
+subprojects/gst-python
-subprojects/gst-rtsp-server/
+subprojects/gst-rtsp-server
-subprojects/gstreamer/
+subprojects/gstreamer
-subprojects/gstreamer-sharp/
+subprojects/gstreamer-sharp
-subprojects/gstreamer-vaapi/
+subprojects/gstreamer-vaapi
-subprojects/glib/
+subprojects/glib
-subprojects/gl-headers/
+subprojects/gl-headers
-subprojects/bindinator/
+subprojects/bindinator
-subprojects/dssim/
+subprojects/dssim
-subprojects/gtk-sharp/
+subprojects/gtk-sharp
-subprojects/libffi/
+subprojects/libffi
-subprojects/libnice/
+subprojects/libnice
-subprojects/libunwind/
+subprojects/libunwind
-subprojects/proxy-libintl/
+subprojects/proxy-libintl
-subprojects/zlib/
+subprojects/zlib
-subprojects/openh264/
+subprojects/openh264
-subprojects/pygobject/
+subprojects/pygobject
-subprojects/pycairo/
+subprojects/pycairo
-subprojects/json-glib/
+subprojects/json-glib
-subprojects/orc/
+subprojects/orc
-subprojects/libsoup/
+subprojects/libsoup
-subprojects/FFmpeg/
+subprojects/FFmpeg
-subprojects/x264/
+subprojects/x264
 prefix/
 pygobject