Updating RAFT tag (#1509)

There was a PR merged into RAFT today, updating to the most recent commit hash : f0cd81f.

Authors:
  - Alex Fender (https://github.com/afender)

Approvers:
  - Seunghwa Kang (https://github.com/seunghwak)
  - Brad Rees (https://github.com/BradReesWork)

URL: #1509

cpp/CMakeLists.txt

@@ -302,7 +302,7 @@ else(DEFINED ENV{RAFT_PATH})
   FetchContent_Declare(
     raft
     GIT_REPOSITORY    https://github.com/rapidsai/raft.git
-    GIT_TAG           6455e05b3889db2b495cf3189b33c2b07bfbebf2
+    GIT_TAG           f0cd81fb49638eaddc9bf18998cc894f292bc293
 
     SOURCE_SUBDIR     raft
   )