fix: split into build and deploy stages

Dockerfile

@@ -1,17 +1,26 @@
-FROM postgres:16
+FROM postgres:16 AS env-build
 
+# install build dependencies
 RUN apt-get update && apt-get -y upgrade \
   && apt-get install -y build-essential libpq-dev postgresql-server-dev-all
 
 WORKDIR /srv
 COPY . /srv
 
+# build extension for all supported versions
 RUN for v in `seq 13 16`; do pg_buildext build-$v $v; done
 
+# create tarball and checksums
 RUN cp sql/pg_uuidv7--1.4.sql . && TARGETS=$(find * -name pg_uuidv7.so) \
   && tar -czvf pg_uuidv7.tar.gz $TARGETS pg_uuidv7--1.4.sql pg_uuidv7.control \
   && sha256sum pg_uuidv7.tar.gz $TARGETS pg_uuidv7--1.4.sql pg_uuidv7.control > SHA256SUMS
 
-RUN cp ${PG_MAJOR}/pg_uuidv7.so /usr/lib/postgresql/${PG_MAJOR}/lib \
-  && cp pg_uuidv7.control /usr/share/postgresql/${PG_MAJOR}/extension \
-  && cp pg_uuidv7--1.4.sql /usr/share/postgresql/${PG_MAJOR}/extension
+FROM postgres:16 AS env-deploy
+
+# copy tarball and checksums
+COPY --from=0 /srv/pg_uuidv7.tar.gz /srv/SHA256SUMS /srv
+
+# add extension to postgres
+COPY --from=0 /srv/${PG_MAJOR}/pg_uuidv7.so /usr/lib/postgresql/${PG_MAJOR}/lib
+COPY --from=0 /srv/pg_uuidv7.control /usr/share/postgresql/${PG_MAJOR}/extension
+COPY --from=0 /srv/pg_uuidv7--1.4.sql /usr/share/postgresql/${PG_MAJOR}/extension