Play release flow

1. Confirm package name and artifact (.aab preferred).
2. Deploy to a testing track first:

gps --package $PKG deploy --file $AAB --track internal --release-notes "$NOTES" --confirm

3. Promote when ready:

gps --package $PKG tracks promote --from internal --to beta --confirm
gps --package $PKG tracks promote --from beta --to production --user-fraction 0.1 --confirm

4. Expand or halt: