Bump llama.cpp from ac43576 to a206137

Bumps [llama.cpp](https://github.com/ggerganov/llama.cpp) from `ac43576` to `a206137`.
- [Release notes](https://github.com/ggerganov/llama.cpp/releases)
- [Commits](ggml-org/llama.cpp@ac43576...a206137)

---
updated-dependencies:
- dependency-name: llama.cpp
  dependency-type: direct:production
...

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