Update ghost

Changes:

- https://github.com/docker-library/ghost/commit/74ddbb6: Update to 5.91.0, ghost-cli 1.26.1

library/ghost

@@ -5,12 +5,12 @@ Maintainers: Tianon Gravi <[email protected]> (@tianon),
              Austin Burdine <[email protected]> (@acburdine)
 GitRepo: https://github.com/docker-library/ghost.git
 
-Tags: 5.90.2, 5.90, 5, latest
+Tags: 5.91.0, 5.91, 5, latest
 Architectures: amd64, arm32v7, arm64v8, ppc64le, s390x
-GitCommit: 5e8b6b027fde03cedaf565a478fce452e51aaea1
+GitCommit: 74ddbb69bd74cbfb03585a004ed33c366ed51160
 Directory: 5/debian
 
-Tags: 5.90.2-alpine, 5.90-alpine, 5-alpine, alpine
+Tags: 5.91.0-alpine, 5.91-alpine, 5-alpine, alpine
 Architectures: amd64, arm32v6, arm32v7, arm64v8
-GitCommit: 5e8b6b027fde03cedaf565a478fce452e51aaea1
+GitCommit: 74ddbb69bd74cbfb03585a004ed33c366ed51160
 Directory: 5/alpine