Upstream drift: Platform packages

[github-actions]

Platform packages — the daily upstream check saw this on 2026-07-30:

• OpenTok.Net.Win: the pinned 2.34.1.4-beta.7.3 no longer downloads from https://api.nuget.org/v3-flatcontainer/opentok.net.win/2.34.1.4-beta.7.3/opentok.net.win.2.34.1.4-beta.7.3.nupkg — builds will fail until the pin moves.
• OpenTok.Net.Win: pinned the prerelease 2.34.1.4-beta.7.3 while 2.34.1.4 is published on nuget.org — a released umbrella must not depend on a beta. Re-pin OpenTokWinPackageVersion in Directory.Build.props.

Pins live in Directory.Build.props; ./build/BumpNativeVersion.sh <version> does the mechanical part.