Update get_rmm.cmake to better support CalVer (#258)

Updates raft's get_rmm.cmake logic to work like cuML and cuGraph, so that it works better with CalVer. This helps when building RAPIDS libraries locally and depending on a local RMM (e.g. with rapids-compose).

Authors:
  - Mark Harris (https://github.com/harrism)

Approvers:
  - Dante Gama Dessavre (https://github.com/dantegd)

URL: #258

cpp/cmake/thirdparty/get_rmm.cmake

@@ -20,13 +20,19 @@ function(find_and_configure_rmm VERSION)
         return()
     endif()
 
+    if(${VERSION} MATCHES [=[([0-9]+)\.([0-9]+)\.([0-9]+)]=])
+        set(MAJOR_AND_MINOR "${CMAKE_MATCH_1}.${CMAKE_MATCH_2}")
+    else()
+        set(MAJOR_AND_MINOR "${VERSION}")
+    endif()
+
     rapids_cpm_find(rmm ${VERSION}
         GLOBAL_TARGETS      rmm::rmm
         BUILD_EXPORT_SET    raft-exports
         INSTALL_EXPORT_SET  raft-exports
         CPM_ARGS
             GIT_REPOSITORY  https://github.com/rapidsai/rmm.git
-            GIT_TAG         branch-${VERSION}
+            GIT_TAG         branch-${MAJOR_AND_MINOR}
             GIT_SHALLOW     TRUE
             OPTIONS         "BUILD_TESTS OFF"
                             "BUILD_BENCHMARKS OFF"
@@ -36,6 +42,6 @@ function(find_and_configure_rmm VERSION)
 
 endfunction()
 
-set(RAFT_MIN_VERSION_rmm "${RAFT_VERSION_MAJOR}.${RAFT_VERSION_MINOR}")
+set(RAFT_MIN_VERSION_rmm "${RAFT_VERSION_MAJOR}.${RAFT_VERSION_MINOR}.00")
 
 find_and_configure_rmm(${RAFT_MIN_VERSION_rmm})