Bump Sources/Copus from dfd6c88 to 61747bc

Bumps [Sources/Copus](https://github.com/xiph/opus) from `dfd6c88` to `61747bc`.
- [Release notes](https://github.com/xiph/opus/releases)
- [Commits](xiph/opus@dfd6c88...61747bc)

---
updated-dependencies:
- dependency-name: Sources/Copus
  dependency-type: direct:production
...

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

Author: dependabot[bot]