use same pip lock file for both platforms to speedup build

Dockerfile

@@ -8,7 +8,7 @@ WORKDIR /gslist
 
 RUN make
 
-FROM python:3.12 AS requirements-stage
+FROM --platform=$BUILDPLATFORM python:3.12 AS requirements-stage
 WORKDIR /tmp
 
 RUN pip install poetry poetry-plugin-export