[SYCL][DOC][Graph] Add Contributor to SYCL-Graph spec (intel#12280)

Add Andrey Alekseenko @al42and to list of SYCL-Graph contributors.

Author: Ewan Crawford

sycl/doc/extensions/experimental/sycl_ext_oneapi_graph.asciidoc

@@ -54,6 +54,7 @@ Bjoern Knafla, Codeplay +
 Lukas Sommer, Codeplay +
 Maxime France-Pillois, Codeplay +
 Ronan Keryell, AMD +
+Andrey Alekseenko, KTH Royal Institute of Technology +
 
 == Dependencies