Release 2020_020 (2020-07-13)

NixOS 19.03 platform

• mailstub: fix handling of system mails emitted on other nodes of the same resource group (e.g., cron job output) (#123375).

• Statshost: update Prometheus to 2.19.2, InfluxDB to 1.8.0 and Grafana to 7.0.4 (#126856, #126663).

• Update Kubernetes to 1.18.5 (#126856).

NixOS 15.09 platform

• Retry system update on failure if update in maintenance is enabled. This is expected to avoid failed maintenance jobs, for example when running planned upgrades to 19.03 (#127000).