Bump ffmpeg-windows-build-helpers from 27b44c0 to 9b6fc4a

Bumps [ffmpeg-windows-build-helpers](https://github.com/rdp/ffmpeg-windows-build-helpers) from `27b44c0` to `9b6fc4a`.
- [Release notes](https://github.com/rdp/ffmpeg-windows-build-helpers/releases)
- [Commits](rdp/ffmpeg-windows-build-helpers@27b44c0...9b6fc4a)

---
updated-dependencies:
- dependency-name: ffmpeg-windows-build-helpers
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>