Add root log to yard.rbi

[dduugg]

Adds the log method in an attempt to solve the problem posted here (and pasted below):

I'm attempting to migrate yard-sorbet to use tapioca for RBI generation. WIP PR: dduugg/yard-sorbet#103
I'm following the migration guide: https://github.com/Shopify/tapioca/wiki/Migrating-to-Tapioca
However, typechecking is currently failing:

$ be srb tc                                                                                                                         [15:52:16]
lib/yard-sorbet/sig_to_yard.rb:60: Method log does not exist on T.class_of(YARDSorbet::SigToYARD) https://srb.help/7003
    60 |        log.info("Unsupported sig aref node #{node.source}")
                ^^^

lib/yard-sorbet/sig_to_yard.rb:126: Method log does not exist on T.class_of(YARDSorbet::SigToYARD) https://srb.help/7003
     126 |      log.warn("Unsupported sig #{node.type} node #{node.source}")
                ^^^
Errors: 2
FAIL

log is defined by yard here: https://github.com/lsegal/yard/blob/main/lib/yard/globals.rb#L20-L22
My understanding is that I should be able to resolve this by adding requiring yard/globals in tapioca/require, then invoking bin/tapioca gem yard, which I attempted to do in these commits:
dduugg/yard-sorbet@9e00ecd
dduugg/yard-sorbet@8717134
However, I'm still seeing the same errors when I attempt to invoke srb tc
What am I doing wrong?