[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 9f63dc3 [SVE] Fix shift-by-imm patterns used by asr, lsl & lsr intrinsics.
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   9f63dc3..dcd4589  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to dcd4589a0d68032076f6951190ab170fef9c3cf5.
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!