docs: drop outdated --pass note and redundant pg-upgrade section

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

README.md

@@ -23,7 +23,7 @@ A platform for community discussion
 
 1. Set up Docker Swarm and [`abra`]
 2. Deploy [`coop-cloud/traefik`]
-3. `abra app new discourse --secrets` (optionally with `--pass` to save secrets in `pass`)
+3. `abra app new discourse --secrets`
 4. `abra app config YOURAPPDOMAIN` — set `DOMAIN` and `DISCOURSE_DEVELOPER_EMAILS`
 5. `abra app deploy YOURAPPDOMAIN`
 6. Open the configured domain in your browser to finish set-up. The first account
@@ -43,12 +43,6 @@ override) so it works behind the reverse proxy.
 abra app run YOURAPPDOMAIN app discourse admin create
 ```
 
-## Postgres major version upgrades
-
-Handled automatically. The `db` entrypoint detects an older data directory on
-deploy and runs `pg_upgrade` in place (it installs the old binaries, detects the
-cluster's real install superuser, and upgrades). No manual dump/restore needed.
-
 ## Migrating from the previous (bitnami) recipe
 
 The official image stores uploads under `/shared` rather than bitnami's