[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at a91e967 [InstCombine] Fold `and(shl(zext(x), width(SIGNMASK) - width(%x)), SIGNMASK)` to `and(sext(%x), SIGNMASK)`
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   a91e967..dfe67f4  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to dfe67f450ef60ce7bd3528b3e2d4326e6ac598ea.
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!