Bump fluent-ffmpeg from 2.1.2 to 2.1.3

Bumps [fluent-ffmpeg](https://github.com/fluent-ffmpeg/node-fluent-ffmpeg) from 2.1.2 to 2.1.3.
- [Commits](fluent-ffmpeg/node-fluent-ffmpeg@v2.1.2...v2.1.3)

---
updated-dependencies:
- dependency-name: fluent-ffmpeg
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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