Update ghost

Changes:

- https://github.com/docker-library/ghost/commit/a71db45: Update to 5.26.3, ghost-cli 1.23.1
- https://github.com/docker-library/ghost/commit/ba0cd7f: Update generated README

library/ghost

@@ -5,14 +5,14 @@ Maintainers: Tianon Gravi <[email protected]> (@tianon),
              Austin Burdine <[email protected]> (@acburdine)
 GitRepo: https://github.com/docker-library/ghost.git
 
-Tags: 5.26.2, 5.26, 5, latest
+Tags: 5.26.3, 5.26, 5, latest
 Architectures: amd64, arm32v7, arm64v8, ppc64le, s390x
-GitCommit: 99e29fe0b96209e2c8d3f88ede432ffe965887bb
+GitCommit: a71db45301e96deaa83048ee336d5c865b274a1f
 Directory: 5/debian
 
-Tags: 5.26.2-alpine, 5.26-alpine, 5-alpine, alpine
+Tags: 5.26.3-alpine, 5.26-alpine, 5-alpine, alpine
 Architectures: amd64, arm32v6, arm32v7, arm64v8
-GitCommit: 99e29fe0b96209e2c8d3f88ede432ffe965887bb
+GitCommit: a71db45301e96deaa83048ee336d5c865b274a1f
 Directory: 5/alpine
 
 Tags: 4.48.9, 4.48, 4