Add cc_proto_aspect to globals.bzl (#88)

Works towards fixing issue reported in
https://github.com/protocolbuffers/protobuf/pull/19576

Protobuf at head needs to expose either built-in or Starlark
cc_proto_aspect.

private/globals.bzl

diff --git a/private/globals.bzl b/private/globals.bzl
index 9945d7e..e6b9944 100644
--- a/private/globals.bzl
+++ b/private/globals.bzl
@@ -34,4 +34,5 @@
     "PyCcLinkParamsProvider": "8.0.0",
     "PyInfo": "8.0.0",
     "PyRuntimeInfo": "8.0.0",
+    "cc_proto_aspect": "8.0.0",
 }