docker-images/postgres-11.4: fix image version regression in 3.15
Created by: slimsag
https://github.com/sourcegraph/deploy-sourcegraph/commit/ccd87ad566b5d62a3e2117509c01c5c5eae9d860#diff-1c41402b2ef772fe0d34e24f1e0d091aR38 changed the image version from 20-04-07_56b20163
to insiders
, unfortunately this regressed the image version back to an older one from 2019 19-11-14_b084311b
-- luckily, nothing much changed in this image during that timeframe except support for most notably non-root Kubernetes environments.
This fixes the regression. Also confirmed that all of the following 'rebranded' images are correct:
- redis-store
- redis-cache
- syntax-highlighter
- indexed-searcher
- search-indexer
I did not manually verify jaeger, grafana, or prometheus since those are built in CI / not rebranded images so they should definitely be OK.