How to update the bindings

Take the updated .gir files (e.g. from your gst-build checkout) and put them in the gir-files directory
In the gir-files directory, run ./fix.sh
In the GstVideo-1.0.gir file, the GST_VIDEO_BUFFER_FLAG_ONEFIELD and GST_VIDEO_FRAME_FLAG_ONEFIELD flags are twice. This is a gir bug. Delete the second one.
If there is a new GStreamer version: Manually update gst*/Cargo.toml
Run generator.py
Investigate the diff, fix any mess-ups, look at commented functions and implement them manually
cargo build
for f in (ls |grep gstreamer); cd $f; cargo build --features v1_18; cd ..; end (or with the new version you just added)