[webvmt] Status Update

1. Progress Made
    i. Raised libheif pull request #1687 [1] to support metadata track encoding in HEIF video files with WebVMT-compliant timestamps.
    ii. Raised libheif pull request #1706 [2] to encode timed metadata in HEIF video files with WebVMT sync commands, including binary data.
    iii. Updated libheif Wiki to document support for timed metadata encoding in HEIF video files [3] using WebVMT.

1. Next Steps
    i. Continue participation in OGC Testbed-21 [4] to study collision monitoring use case using geotagged video from dash cam fleet.
    ii. Continue alignment discussions with OGC GeoPose SWG [5].
    iii. Continue participation in WICG DataCue [6].
    iv. Continue collaboration in W3C Sync on the Web Community Group [7]. 
    v. Continue community outreach and identify more activities to promote progress towards the standardisation track.

[1] https://github.com/strukturag/libheif/pull/1687
[2] https://github.com/strukturag/libheif/pull/1706
[3] https://github.com/away-team-software/libheif/wiki/heif%E2%80%90enc-Command-Line-Tool#adding-a-metadata-track
[4] https://www.ogc.org/initiatives/ogc-testbed-21/
[5] https://www.ogc.org/projects/groups/geoposeswg
[6] https://github.com/WICG/datacue
[7] https://www.w3.org/community/sync-on-the-web/