Update haproxy

Changes:

- https://github.com/docker-library/haproxy/commit/a313613: Update to 2.3-dev6

library/haproxy

@@ -4,14 +4,14 @@ Maintainers: Tianon Gravi <[email protected]> (@tianon),
              Joseph Ferguson <[email protected]> (@yosifkit)
 GitRepo: https://github.com/docker-library/haproxy.git
 
-Tags: 2.3-dev5, 2.3-dev
+Tags: 2.3-dev6, 2.3-dev
 Architectures: amd64, arm32v5, arm32v7, arm64v8, i386, mips64le, ppc64le, s390x
-GitCommit: 7628980bbcbc5b88ef3f6a2c9aa66a5728dc6e2b
+GitCommit: a3136139767f5ee652493820868b7c0c19344069
 Directory: 2.3-rc
 
-Tags: 2.3-dev5-alpine, 2.3-dev-alpine
+Tags: 2.3-dev6-alpine, 2.3-dev-alpine
 Architectures: amd64, arm32v6, arm32v7, arm64v8, i386, ppc64le, s390x
-GitCommit: 7628980bbcbc5b88ef3f6a2c9aa66a5728dc6e2b
+GitCommit: a3136139767f5ee652493820868b7c0c19344069
 Directory: 2.3-rc/alpine
 
 Tags: 2.2.4, 2.2, latest, lts