Update ghost

Changes:

- https://github.com/docker-library/ghost/commit/c87e92c: Update to 3.39.3, ghost-cli 1.15.2

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: 3.39.2, 3.39, 3, latest
+Tags: 3.39.3, 3.39, 3, latest
 Architectures: amd64, arm32v7, arm64v8, ppc64le, s390x
-GitCommit: 4e13f4573c049eff193bf7f8fb61b9f1da483b9b
+GitCommit: c87e92c8021a6ba40815cbbe855c9031cde4a72f
 Directory: 3/debian
 
-Tags: 3.39.2-alpine, 3.39-alpine, 3-alpine, alpine
+Tags: 3.39.3-alpine, 3.39-alpine, 3-alpine, alpine
 Architectures: amd64, arm32v6, arm32v7, arm64v8
-GitCommit: 4e13f4573c049eff193bf7f8fb61b9f1da483b9b
+GitCommit: c87e92c8021a6ba40815cbbe855c9031cde4a72f
 Directory: 3/alpine
 
 Tags: 2.38.2, 2.38, 2