fix: update dockerfile with corepack so we can use yarn v4

Dockerfile

@@ -1,8 +1,10 @@
 # Build stage
 FROM node:20-alpine AS builder
 WORKDIR /app
+# Enable Corepack so we can use Yarn v4
+RUN corepack enable && corepack prepare yarn@stable --activate
 COPY package.json yarn.lock ./
-RUN yarn install --frozen-lockfile
+RUN yarn install --immutable
 COPY . .
 RUN yarn build