fix: make the env vars available to containers created during the pre-release process

We still re-add them in the builder-release phase to ensure users don't set incorrect ones in a custom trigger.

plugins/builder-herokuish/dockerfiles/builder-pre-release.Dockerfile

@@ -0,0 +1,5 @@
+ARG APP_IMAGE
+FROM $APP_IMAGE
+
+ARG DOKKU_APP_USER herokuishuser
+COPY --chown=$DOKKU_APP_USER 00-global-env.sh 01-app-env.sh /app/.profile.d/