[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at e6aa065 [NFC, Refactor] Modernize the TypeSpecifierWidth enum (Specifiers.h) to a scoped enum
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   e6aa065..7fa8b62  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 7fa8b629208c98efa883f7a0e1d51de1d21b104c.
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!