Fix draco compilation on gcc11

The previous version breaks on Fedora 34, and likely other distros
with recent compilers due to not including cstddef and limits headers.

This is already fixed upstream, but only in master. And looking at
google/draco#704 there may be compatibility issues with using the
latest code.

So for now we're upgrading from 1.3.3 to 1.3.6 and adding the fix.

cmake/ports/draco/portfile.cmake

@@ -19,9 +19,9 @@ include(vcpkg_common_functions)
 
 vcpkg_from_github(
     OUT_SOURCE_PATH SOURCE_PATH
-    REPO google/draco
-    REF 1.3.3
-    SHA512 80ed5a623046822f5bb26b2454c8ee8cc93ffe9eb3012e8461cefdfc577b26d69a92ea0f0c5e14f5f48c1ef99f9a7263b01710df376792e74358ae14e49c3897
+    REPO vircadia/draco
+    REF 1.3.6-fixed
+    SHA512 7980b1a0a559719500302133c4616162b0731c5f111507bd2829e809f85ca2ccc509fac7ae6b75a4000ce8431b20301f4c6c896c65fa4fd0d0bdf4680a1febe3
     HEAD_REF master
 )