react-express-mysql: get version from mysql

Signed-off-by: Jérémie Drouet <jeremie.drouet@gmail.com>

react-express-mysql/backend/Dockerfile

@@ -15,7 +15,7 @@ EXPOSE $PORT 9229 9230
 
 COPY package.json /code/package.json
 COPY package-lock.json /code/package-lock.json
-RUN npm ci && npm cache clean --force
+RUN npm ci
 
 # check every 30s to ensure this service returns HTTP 200
 HEALTHCHECK --interval=30s \