Update ghost

Changes:

- https://github.com/docker-library/ghost/commit/42a40f8: Update to 3.21.0, ghost-cli 1.14.1
- https://github.com/docker-library/ghost/commit/7d224d7: Update to 3.20.3, ghost-cli 1.14.1

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: 3.20.2, 3.20, 3, latest
+Tags: 3.21.0, 3.21, 3, latest
 Architectures: amd64, arm32v7, arm64v8, ppc64le, s390x
-GitCommit: 21a896fb737d54e16ed3fe308fb88e32fd836435
+GitCommit: 42a40f8b10671dc7f4073a27cab1e671f68d8c97
 Directory: 3/debian
 
-Tags: 3.20.2-alpine, 3.20-alpine, 3-alpine, alpine
+Tags: 3.21.0-alpine, 3.21-alpine, 3-alpine, alpine
 Architectures: amd64, arm32v6, arm32v7, arm64v8, i386, ppc64le, s390x
-GitCommit: 21a896fb737d54e16ed3fe308fb88e32fd836435
+GitCommit: 42a40f8b10671dc7f4073a27cab1e671f68d8c97
 Directory: 3/alpine
 
 Tags: 2.38.2, 2.38, 2