[www-scripts] Clang Attribute Doc Update: ERROR

[root via www-scripts]

UPDATING LLVM SOURCES
HEAD is now at 1af3cb5 [llvm-readobj/libObject] - Allow dumping objects that has a broken SHT_SYMTAB_SHNDX section.
>From https://github.com/llvm/llvm-project
 * branch            master     -> FETCH_HEAD
   1af3cb5..4b9fa3b  master     -> origin/master
First, rewinding head to replay your work on top of it...
Fast-forwarded master to 4b9fa3b705c8280e71908f4cc8c115320ef48316.
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!