[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at e4d2793 [NFC, Refactor] Rename the (scoped) enum DeclaratorContext's enumerators to remove duplication
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   e4d2793..2262393  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 22623930903dd7922a0ee06d4f43fc74e0053e3d.
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!