Use alpine and production dependencies, but cleanup build dependencie…

…s afterward.

Dockerfile

@@ -9,6 +9,9 @@ FROM node:20-alpine
 WORKDIR /app
 ENV NODE_ENV=production
 COPY package*.json ./
-RUN npm ci
+# We need to install `alpine-sdk` and `python3` to build `@discordjs/opus`
+RUN apk add --no-cache --virtual .build-deps alpine-sdk python3 \
+    && npm ci --production \
+    && apk del .build-deps
 COPY --from=builder /app/out ./out
 CMD [ "node", "out/index.js" ]