Update postgres

Changes:

- docker-library/postgres@4ce5329: Merge pull request docker-library/postgres#961 from infosiftr/pg15
- docker-library/postgres@90f8530: Add 15 pre-release

Author: docker-library-bot

library/postgres

@@ -4,6 +4,16 @@ Maintainers: Tianon Gravi <[email protected]> (@tianon),
              Joseph Ferguson <[email protected]> (@yosifkit)
 GitRepo: https://github.com/docker-library/postgres.git
 
+Tags: 15beta1, 15beta1-bullseye
+Architectures: amd64, arm32v5, arm32v7, arm64v8, i386, mips64le, ppc64le, s390x
+GitCommit: 90f8530900c29714bae8f6045c6749d5fbe527c0
+Directory: 15/bullseye
+
+Tags: 15beta1-alpine, 15beta1-alpine3.15
+Architectures: amd64, arm32v6, arm32v7, arm64v8, i386, ppc64le, s390x
+GitCommit: 90f8530900c29714bae8f6045c6749d5fbe527c0
+Directory: 15/alpine
+
 Tags: 14.3, 14, latest, 14.3-bullseye, 14-bullseye, bullseye
 Architectures: amd64, arm32v5, arm32v7, arm64v8, i386, mips64le, ppc64le, s390x
 GitCommit: 4e56664f1797ba4cc0f5917b6d794792a5571b45