build(deps): bump third-party/ffmpeg-windows-x86_64

Bumps [third-party/ffmpeg-windows-x86_64](https://github.com/LizardByte/build-deps) from `211737b` to `1685f4a`.
- [Commits](LizardByte/build-deps@211737b...1685f4a)

---
updated-dependencies:
- dependency-name: third-party/ffmpeg-windows-x86_64
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>