This modification fix the following error.

```console
$ docker run alpine-groonga-test-01
Error loading shared library libgomp.so.1: No such file or directory (needed by /usr/lib/libgroonga.so.0) Error relocating /usr/lib/libgroonga.so.0: GOMP_parallel: symbol not found Error relocating１１ /usr/lib/libgroonga.so.0: GOMP_single_start: symbol not found Error relocating /usr/lib/libgroonga.so.0: omp_get_num_threads: symbol not found Error relocating /usr/lib/libgroonga.so.0: GOMP_barrier: symbol not found Error relocating /usr/lib/libgroonga.so.0: omp_get_thread_num: symbol not found
```

llama.cpp uses OpenMP.
However, we had not installed libgomp in alpine docker image. So, we
install libgomp in alpine docker image in this docker image in this
modification.