[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 0d2fe90 AMDGPU/GlobalISel: Use more accurate legality rules for merge/unmerge
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   0d2fe90..bd5ca4f  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to bd5ca4f0ed4adfa29150c18a621acb3e71d41450.
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!