fix: add psycopg2-binary to runtime deps (CAR-1422)
CI passed: lint+test green (run 3779/8090 rerun success).
Unblocks alembic upgrade head in standalone image.
Co-Authored-By: Paperclip <noreply@paperclip.ing>
alembic upgrade head uses SQLAlchemy sync engine with postgresql:// URL,
which requires psycopg2. The old image had it via cartsnitch-common;
standalone image needs it explicit.
Co-Authored-By: Paperclip <noreply@paperclip.ing>