Update memcached

Changes:

- https://github.com/docker-library/memcached/commit/8ccbd92: Merge pull request https://github.com/docker-library/memcached/pull/75 from J0WI/alpine-3.15
- https://github.com/docker-library/memcached/commit/d8dc76b: Alpine 3.15

library/memcached

@@ -9,7 +9,7 @@ Architectures: amd64, arm32v5, arm32v7, arm64v8, i386, mips64le, ppc64le, s390x
 GitCommit: e0b2a7e2288f313824b2e860d6225d3fd018a7f7
 Directory: debian
 
-Tags: 1.6.12-alpine, 1.6-alpine, 1-alpine, alpine, 1.6.12-alpine3.14, 1.6-alpine3.14, 1-alpine3.14, alpine3.14
+Tags: 1.6.12-alpine, 1.6-alpine, 1-alpine, alpine, 1.6.12-alpine3.15, 1.6-alpine3.15, 1-alpine3.15, alpine3.15
 Architectures: amd64, arm32v7, arm64v8, i386, ppc64le, s390x
-GitCommit: 2f7d163ec21401699a4f87e6e293b2ed45227598
+GitCommit: d8dc76b68917cb51e3ecbbf0fc85ca6afc53902a
 Directory: alpine