[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at f6615b2 Update FIR registration to not rely on the global MLIR dialect registry (NFC)
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   f6615b2..2b37174  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 2b37174b9a5db235e493cb72e4454cc08a1b1791.
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!