Upgrade prometheus_postgres_exporter (v0.11.1-2 -> v0.12.0-0)

requirements.yml

@@ -34,7 +34,7 @@
   version: v1.5.0-6
 
 - src: git+https://gitlab.com/etke.cc/roles/prometheus_postgres_exporter.git
-  version: v0.11.1-2
+  version: v0.12.0-0
 
 - src: git+https://gitlab.com/etke.cc/roles/backup_borg.git
   version: v1.2.3-1.7.9-0