pbutils: add some missing gi annotations
For allow-none parameters
- gst-libs/gst/pbutils/encoding-profile.c 4 additions, 4 deletionsgst-libs/gst/pbutils/encoding-profile.c
- gst-libs/gst/pbutils/encoding-target.c 2 additions, 2 deletionsgst-libs/gst/pbutils/encoding-target.c
- gst-libs/gst/pbutils/gstdiscoverer.c 5 additions, 4 deletionsgst-libs/gst/pbutils/gstdiscoverer.c