Add sciml-bench submodule to workflows

.gitmodules

@@ -1,3 +1,6 @@
 [submodule "pytorch_GAN_zoo"]
 	path = workflows/pytorch_GAN_zoo/pytorch_GAN_zoo
 	url = https://github.com/facebookresearch/pytorch_GAN_zoo.git
+[submodule "workflows/sciml-bench/sciml-bench"]
+	path = workflows/sciml-bench/sciml-bench
+	url = git@github.com:stfc-sciml/sciml-bench.git

workflows/sciml-bench/sciml-bench

@@ -0,0 +1 @@
+Subproject commit 2c5035d4ea57ee7d2cde8ef805b756fc2d061f92