Update ghost

Changes:

- https://github.com/docker-library/ghost/commit/2b140e1: Update to 5.3.0, ghost-cli 1.21.0

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: 5.2.4, 5.2, 5, latest
+Tags: 5.3.0, 5.3, 5, latest
 Architectures: amd64, arm32v7, arm64v8, ppc64le, s390x
-GitCommit: dde7fc8bda41a968dadc4f7e8b070e4dbf27e76f
+GitCommit: 2b140e1df6d75ed63c391549262b3c9b80e015f2
 Directory: 5/debian
 
-Tags: 5.2.4-alpine, 5.2-alpine, 5-alpine, alpine
+Tags: 5.3.0-alpine, 5.3-alpine, 5-alpine, alpine
 Architectures: amd64, arm32v6, arm32v7, arm64v8
-GitCommit: dde7fc8bda41a968dadc4f7e8b070e4dbf27e76f
+GitCommit: 2b140e1df6d75ed63c391549262b3c9b80e015f2
 Directory: 5/alpine
 
 Tags: 4.48.2, 4.48, 4