Update memcached

Changes:

- https://github.com/docker-library/memcached/commit/f7015c3: Update to 1.6.15

library/memcached

@@ -4,12 +4,12 @@ Maintainers: Tianon Gravi <[email protected]> (@tianon),
              Joseph Ferguson <[email protected]> (@yosifkit)
 GitRepo: https://github.com/docker-library/memcached.git
 
-Tags: 1.6.14, 1.6, 1, latest, 1.6.14-bullseye, 1.6-bullseye, 1-bullseye, bullseye
+Tags: 1.6.15, 1.6, 1, latest, 1.6.15-bullseye, 1.6-bullseye, 1-bullseye, bullseye
 Architectures: amd64, arm32v5, arm32v7, arm64v8, i386, mips64le, ppc64le, s390x
-GitCommit: 2826e6e778859732667a4eca2a84b47d5f3c4892
+GitCommit: f7015c3dba3b87f3793f217db5e06ceec77f43ee
 Directory: debian
 
-Tags: 1.6.14-alpine, 1.6-alpine, 1-alpine, alpine, 1.6.14-alpine3.15, 1.6-alpine3.15, 1-alpine3.15, alpine3.15
+Tags: 1.6.15-alpine, 1.6-alpine, 1-alpine, alpine, 1.6.15-alpine3.15, 1.6-alpine3.15, 1-alpine3.15, alpine3.15
 Architectures: amd64, arm32v7, arm64v8, i386, ppc64le, s390x
-GitCommit: 2826e6e778859732667a4eca2a84b47d5f3c4892
+GitCommit: f7015c3dba3b87f3793f217db5e06ceec77f43ee
 Directory: alpine