docker: bump base image

Dockerfile

@@ -1,5 +1,6 @@
-# waiting for nodejs/docker-node#2081
-FROM node:20.12 as builder
+FROM node:slim AS builder
+
+WORKDIR /disco
 
 COPY package*.json .
 COPY isomorphic-wrtc/package.json isomorphic-wrtc/
@@ -17,23 +18,25 @@ RUN npm --workspace=discojs --workspace=discojs-node run build
 COPY server/ server/
 RUN cd server/ && npm run build
 
-FROM node:20.12-slim as runner
+FROM node:slim AS runner
+
+WORKDIR /disco
 
-COPY --link --from=builder package*.json .
-COPY --link --from=builder isomorphic-wrtc/package.json isomorphic-wrtc/
-COPY --link --from=builder discojs/package.json discojs/
-COPY --link --from=builder discojs-node/package.json discojs-node/
-COPY --link --from=builder server/package.json server/
+COPY --link --from=builder /disco/package*.json /disco/
+COPY --link --from=builder /disco/isomorphic-wrtc/package.json isomorphic-wrtc/
+COPY --link --from=builder /disco/discojs/package.json discojs/
+COPY --link --from=builder /disco/discojs-node/package.json discojs-node/
+COPY --link --from=builder /disco/server/package.json server/
 RUN npm --workspace=isomorphic-wrtc \
 	--workspace=discojs \
 	--workspace=discojs-node \
 	--workspace=server \
 	--omit=dev ci
 
-COPY --link --from=builder isomorphic-wrtc/node.js isomorphic-wrtc/
-COPY --link --from=builder discojs/dist/ discojs/dist/
-COPY --link --from=builder discojs-node/dist/ discojs-node/dist/
-COPY --link --from=builder server/dist/ server/dist/
+COPY --link --from=builder /disco/isomorphic-wrtc/node.js isomorphic-wrtc/
+COPY --link --from=builder /disco/discojs/dist/ discojs/dist/
+COPY --link --from=builder /disco/discojs-node/dist/ discojs-node/dist/
+COPY --link --from=builder /disco/server/dist/ server/dist/
 
-WORKDIR server/
+WORKDIR server
 CMD ["node", "dist/run_server.js"]