deps: update boringssl

Fixes #319 (MacOS curl build failure).
diff --git a/deps/boringssl b/deps/boringssl
index 8fe1584..f50a8a7 160000
--- a/deps/boringssl
+++ b/deps/boringssl
@@ -1 +1 @@
-Subproject commit 8fe1584023006c844816dbf63fb776b7f84b88b3
+Subproject commit f50a8a77bdab244267f3f70420ed7ef0eaa6d69e