Update rabbitmq

Changes:

- https://github.com/docker-library/rabbitmq/commit/fa38ea2: Update 3.8-rc to 3.8.12-rc.3
- https://github.com/docker-library/rabbitmq/commit/ae14374: Test multiple Erlang versions looking for SHA256

library/rabbitmq

@@ -4,22 +4,22 @@ Maintainers: Tianon Gravi <[email protected]> (@tianon),
              Joseph Ferguson <[email protected]> (@yosifkit)
 GitRepo: https://github.com/docker-library/rabbitmq.git
 
-Tags: 3.8.12-rc.1, 3.8-rc
+Tags: 3.8.12-rc.3, 3.8-rc
 Architectures: amd64, arm32v7, arm64v8, i386, ppc64le, s390x
-GitCommit: 496f4b6b3e52a3e71812e698cda34796f9668c9a
+GitCommit: fa38ea2b55e55ddcbefeb8907a8572e6a5bb5e5a
 Directory: 3.8-rc/ubuntu
 
-Tags: 3.8.12-rc.1-management, 3.8-rc-management
+Tags: 3.8.12-rc.3-management, 3.8-rc-management
 Architectures: amd64, arm32v7, arm64v8, i386, ppc64le, s390x
 GitCommit: 7e63843da6bfb191ddee6dbe3dd7ec0df36ae70b
 Directory: 3.8-rc/ubuntu/management
 
-Tags: 3.8.12-rc.1-alpine, 3.8-rc-alpine
+Tags: 3.8.12-rc.3-alpine, 3.8-rc-alpine
 Architectures: amd64, arm32v6, arm32v7, arm64v8, i386, ppc64le, s390x
-GitCommit: 496f4b6b3e52a3e71812e698cda34796f9668c9a
+GitCommit: fa38ea2b55e55ddcbefeb8907a8572e6a5bb5e5a
 Directory: 3.8-rc/alpine
 
-Tags: 3.8.12-rc.1-management-alpine, 3.8-rc-management-alpine
+Tags: 3.8.12-rc.3-management-alpine, 3.8-rc-management-alpine
 Architectures: amd64, arm32v6, arm32v7, arm64v8, i386, ppc64le, s390x
 GitCommit: 7e63843da6bfb191ddee6dbe3dd7ec0df36ae70b
 Directory: 3.8-rc/alpine/management