bojimans: Fix postgresql version

Otherwise, puppet refuses to apply [1].

[1]
```
Error: Could not retrieve catalog from remote server: Error 500 on SERVER: Server Error: Evaluation Error: Error while evaluating a Function Call, No preferred version defined or automatically detected. (file: /etc/puppet/code/environments
/production/modules/postgresql/manifests/globals.pp, line: 228, column: 5) on node bojimans.internal.softwareheritage.org
Warning: Not using cache on failed catalog
Error: Could not retrieve catalog; skipping run
```

Related to T3802

data/hostname/bojimans.internal.softwareheritage.org.yaml

@@ -4,3 +4,6 @@ networks:
     address: 192.168.100.199
     netmask: 24
     gateway: 192.168.100.1
+
+swh::postgresql::version: "11"
+postgresql::globals::version: "%{alias('swh::postgresql::version')}"

[Phabricator Migration user]

Some references in the commit message have been migrated:

• T3802 is now swh/meta#3802 (closed)