Update memcached

Changes:

- https://github.com/docker-library/memcached/commit/4b85b87: Merge pull request https://github.com/docker-library/memcached/pull/48 from beornf/sasl-pwdb
- https://github.com/docker-library/memcached/commit/d7ef163: Adjust installation of SASL modules to be more explicit/obvious and adjust package removal in Debian to be more automatic
- https://github.com/docker-library/memcached/commit/3eeaebd: Add SASL password file support with PLAIN mechanism

library/memcached

@@ -6,10 +6,10 @@ GitRepo: https://github.com/docker-library/memcached.git
 
 Tags: 1.5.16, 1.5, 1, latest
 Architectures: amd64, arm32v5, arm32v7, arm64v8, i386, ppc64le, s390x
-GitCommit: 3d913e037455832102c16ebac505cc347b8cb426
+GitCommit: d7ef16344d5c0199a41dba750b2da7f733360cb7
 Directory: debian
 
 Tags: 1.5.16-alpine, 1.5-alpine, 1-alpine, alpine
 Architectures: amd64, arm32v6, arm32v7, arm64v8, i386, ppc64le, s390x
-GitCommit: 3d913e037455832102c16ebac505cc347b8cb426
+GitCommit: d7ef16344d5c0199a41dba750b2da7f733360cb7
 Directory: alpine