[ck] Add myself as Memory's maintainer

Hi,  All I've been working on linux kernel memory over the past few years,   making some contributions in the field and alway helping review the related code. Here are some highlight contributions from myself: 1、Implement the cold slab design and development.  It aims to reclaim the kernel slab memory to      reduce the unexpected stability issues and saving some memory space.  The feautre has widely      applied to alibaba group. 2、Implement the swap high feature in cgroup v1 and make use of oomd to proactive kill in the process      rather than trigger the Oom killer in the kernel,  which aims to decrease the risk of unexpected hang      or Oom.  hence the user can control  when to kill and what process to kill.      The ability has been applied to ASI control components. 3、 Design and implement the  performance optimization to reduce the cost for redis snapshot.       The performance benifits is that the whole cost from second to millisecond. 4、Design and implement the dup page in the early stage.  It's proved that has a great improvments when      the app  will access the remote binary program frequently. 5、Backport mglru feature to make the page to identify the cold and hot and implement proactiving the anonymous page with     zswap and file page to reclaim within the reasonable refault value.     Flink has take use of the alibity in the product environment to achieve the goals of saving the memory about at least 5% only     in page cache. With the above key contributions,  I think I am qualified with the job.  Thanks