Update ghost

Changes:

- https://github.com/docker-library/ghost/commit/5de0cce: Merge pull request https://github.com/docker-library/ghost/pull/323 from infosiftr/breaking-change-mysql
- https://github.com/docker-library/ghost/commit/ad07986: Update to 5.9.4, ghost-cli 1.22.0
- https://github.com/docker-library/ghost/commit/da02fe1: Update to 5.9.3, ghost-cli 1.22.0
- https://github.com/docker-library/ghost/commit/e2ba2f8: Update to 5.9.1, ghost-cli 1.22.0

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: 5.8.3, 5.8, 5, latest
+Tags: 5.9.4, 5.9, 5, latest
 Architectures: amd64, arm32v7, arm64v8, ppc64le, s390x
-GitCommit: 825448fb4d55ad66a2c267bdc8b1490d4b318eb8
+GitCommit: 5de0cce1e7ae9470a7dbdbbf776c623a3f1c7170
 Directory: 5/debian
 
-Tags: 5.8.3-alpine, 5.8-alpine, 5-alpine, alpine
+Tags: 5.9.4-alpine, 5.9-alpine, 5-alpine, alpine
 Architectures: amd64, arm32v6, arm32v7, arm64v8
-GitCommit: 825448fb4d55ad66a2c267bdc8b1490d4b318eb8
+GitCommit: 5de0cce1e7ae9470a7dbdbbf776c623a3f1c7170
 Directory: 5/alpine
 
 Tags: 4.48.2, 4.48, 4