add wycheproof submodule

This is used with the pyca/cryptography test suite

Reviewed-by: Tomas Mraz <tomas@openssl.org>
Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Shane Lontis <shane.lontis@oracle.com>
Reviewed-by: Paul Dale <pauli@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/15018)

.gitmodules

@@ -10,3 +10,6 @@
 	path = gost-engine
 	url = https://github.com/gost-engine/engine
 	update = rebase
+[submodule "wycheproof"]
+	path = wycheproof
+	url = https://github.com/google/wycheproof

wycheproof

@@ -0,0 +1 @@
+Subproject commit 2196000605e45d91097147c9c71f26b72af58003