Update ghost

Changes:

- https://github.com/docker-library/ghost/commit/1791d76: Update to 4.48.1, ghost-cli 1.21.0
- https://github.com/docker-library/ghost/commit/b72aca6: Update to 5.1.1, ghost-cli 1.21.0
- https://github.com/docker-library/ghost/commit/5e86836: Update to 5.1.0, ghost-cli 1.21.0

library/ghost

@@ -4,22 +4,22 @@ Maintainers: Tianon Gravi <[email protected]> (@tianon),
              Joseph Ferguson <[email protected]> (@yosifkit)
 GitRepo: https://github.com/docker-library/ghost.git
 
-Tags: 5.0.2, 5.0, 5, latest
+Tags: 5.1.1, 5.1, 5, latest
 Architectures: amd64, arm32v7, arm64v8, ppc64le, s390x
-GitCommit: ad01b8cd0eac82bbe8f7840bc8ac0d3a8b774710
+GitCommit: b72aca608fbecd57cf7692b1cbf0786b18403e05
 Directory: 5/debian
 
-Tags: 5.0.2-alpine, 5.0-alpine, 5-alpine, alpine
+Tags: 5.1.1-alpine, 5.1-alpine, 5-alpine, alpine
 Architectures: amd64, arm32v6, arm32v7, arm64v8
-GitCommit: ad01b8cd0eac82bbe8f7840bc8ac0d3a8b774710
+GitCommit: b72aca608fbecd57cf7692b1cbf0786b18403e05
 Directory: 5/alpine
 
-Tags: 4.48.0, 4.48, 4
+Tags: 4.48.1, 4.48, 4
 Architectures: amd64, arm32v7, arm64v8, ppc64le, s390x
-GitCommit: 054059f2f023935959eac76bf95a49579a034010
+GitCommit: 1791d76b54348818da6cd4281ea6e2be0b757049
 Directory: 4/debian
 
-Tags: 4.48.0-alpine, 4.48-alpine, 4-alpine
+Tags: 4.48.1-alpine, 4.48-alpine, 4-alpine
 Architectures: amd64, arm32v6, arm32v7, arm64v8
-GitCommit: 054059f2f023935959eac76bf95a49579a034010
+GitCommit: 1791d76b54348818da6cd4281ea6e2be0b757049
 Directory: 4/alpine