Update docker-library images

- `ghost`: 1.12.1
- `postgres`: 9.6.5-1.pgdg80+2
- `rocket.chat`: 0.58.4

library/ghost

@@ -4,14 +4,14 @@ Maintainers: Tianon Gravi <[email protected]> (@tianon),
              Joseph Ferguson <[email protected]> (@yosifkit)
 GitRepo: https://github.com/docker-library/ghost.git
 
-Tags: 1.12.0, 1.12, 1, latest
+Tags: 1.12.1, 1.12, 1, latest
 Architectures: amd64, arm32v7, arm64v8, ppc64le, s390x
-GitCommit: 2ef499bc13d24c2ec222bf2e8b0e6abadc81d211
+GitCommit: cc73035bd286b3169d04522cfa64f24daa8e76c2
 Directory: 1/debian
 
-Tags: 1.12.0-alpine, 1.12-alpine, 1-alpine, alpine
+Tags: 1.12.1-alpine, 1.12-alpine, 1-alpine, alpine
 Architectures: amd64
-GitCommit: 2ef499bc13d24c2ec222bf2e8b0e6abadc81d211
+GitCommit: cc73035bd286b3169d04522cfa64f24daa8e76c2
 Directory: 1/alpine
 
 Tags: 0.11.11, 0.11, 0

library/postgres

@@ -16,7 +16,7 @@ Directory: 10/alpine
 
 Tags: 9.6.5, 9.6, 9
 Architectures: amd64, arm32v5, arm32v7, arm64v8, i386, ppc64le, s390x
-GitCommit: bef8f02d1fe2bb4547280ba609f19abd20230180
+GitCommit: b7cb3c6eacea93be2259381033be3cc435649369
 Directory: 9.6
 
 Tags: 9.6.5-alpine, 9.6-alpine, 9-alpine

library/rocket.chat

@@ -1,5 +1,5 @@
 Maintainers: Rocket.Chat Image Team <[email protected]> (@RocketChat)
 GitRepo: https://github.com/RocketChat/Docker.Official.Image.git
 
-Tags: 0.58.3, 0.58, 0, latest
-GitCommit: 20710b313fc4e39f8909322d3901e458a63848ad
+Tags: 0.58.4, 0.58, 0, latest
+GitCommit: 5b8ac5413b368022ea3a3fc455fefa875941058e