javalite: don't use deprecated single_file option

protobuf.bzl

@@ -127,7 +127,7 @@ proto_gen = rule(
         "protoc": attr.label(
             cfg = "host",
             executable = True,
-            single_file = True,
+            allow_single_file = True,
             mandatory = True,
         ),
         "plugin": attr.label(