build: enable shared libs in docker build

Author: dhdaines

Dockerfile

@@ -6,7 +6,7 @@ RUN apk add --no-cache cmake ninja gcc musl-dev python3-dev pkgconfig
 
 COPY . /pocketsphinx
 WORKDIR /pocketsphinx
-RUN cmake -S . -B build -G Ninja && cmake --build build --target install
+RUN cmake -S . -B build -DBUILD_SHARED_LIBS=ON -G Ninja && cmake --build build --target install
 # Cannot use --build-option because pip sucks
 RUN CMAKE_ARGS="-DUSE_INSTALLED_POCKETSPHINX=ON" pip wheel -v .