Dockerfile: Add commented line for ARM64 build missing pre-built pnpm pkg

Dockerfile

@@ -4,6 +4,9 @@ ENV PNPM_HOME="/pnpm"
 ENV PATH="$PNPM_HOME:$PATH"
 RUN corepack enable
 
+# Add build dependencies to build `pnpm` which does not have pre-built packages for ARM64
+# RUN apk add --no-cache python3 make gcc g++
+
 # --- prod dependencies only
 FROM node AS deps
 WORKDIR /squid