Bump version to 20.1.2 (#132293)

Author: tstellar

cmake/Modules/LLVMVersion.cmake

@@ -7,7 +7,7 @@ if(NOT DEFINED LLVM_VERSION_MINOR)
   set(LLVM_VERSION_MINOR 1)
 endif()
 if(NOT DEFINED LLVM_VERSION_PATCH)
-  set(LLVM_VERSION_PATCH 1)
+  set(LLVM_VERSION_PATCH 2)
 endif()
 if(NOT DEFINED LLVM_VERSION_SUFFIX)
   set(LLVM_VERSION_SUFFIX)