alpine: add a missing dependency library

This modification fix the following error.

$ 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 use 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.

alpine/Dockerfile

@@ -65,6 +65,7 @@ RUN \
     libarrow \
     libedit \
     libevent \
+    libgomp \
     libstemmer \
     lz4 \
     msgpack-c \