[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at dc693a0 [MLIR][SPIRVToLLVM] Removed std to llvm patterns from the conversion
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   dc693a0..038edf6  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 038edf6029bafe70b1f7165abe2b0e61ddf506b3.
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!