Update ghost

Changes:

- https://github.com/docker-library/ghost/commit/7959286: Update to 4.40.0, ghost-cli 1.18.2

library/ghost

@@ -4,12 +4,12 @@ Maintainers: Tianon Gravi <[email protected]> (@tianon),
              Joseph Ferguson <[email protected]> (@yosifkit)
 GitRepo: https://github.com/docker-library/ghost.git
 
-Tags: 4.39.1, 4.39, 4, latest
+Tags: 4.40.0, 4.40, 4, latest
 Architectures: amd64, arm32v7, arm64v8, ppc64le, s390x
-GitCommit: 77ef61b959735812f99f64ff37c963896f078494
+GitCommit: 79592863c40301aafe0093b86002066c705d2283
 Directory: 4/debian
 
-Tags: 4.39.1-alpine, 4.39-alpine, 4-alpine, alpine
+Tags: 4.40.0-alpine, 4.40-alpine, 4-alpine, alpine
 Architectures: amd64, arm32v6, arm32v7, arm64v8
-GitCommit: 77ef61b959735812f99f64ff37c963896f078494
+GitCommit: 79592863c40301aafe0093b86002066c705d2283
 Directory: 4/alpine