[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at cf4aa68 [RISCV][ASAN] mark asan as supported for RISCV64 and enable tests
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   cf4aa68..3423d5c  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 3423d5c9da812b0076d1cf14e96ce453e35257b6.
CMake Error at CMakeLists.txt:3 (cmake_minimum_required):
  CMake 3.13.4 or higher is required.  You are running version 3.7.1


-- Configuring incomplete, errors occurred!