When the build is running with a base ruby then generating `x64-ucrt-ruby320.rc`
could fail due to a missing dependency to `x64-mingw-ucrt-fake.rb`.
This commit adds this dependency.

A failing build looks like so:
```
generating x64-mingw-ucrt-fake.rb
generating x64-ucrt-ruby320.rc
../snapshot-master/win32/resource.rb:in `require': cannot load such file -- ./x64-mingw-ucrt-fake (LoadError)
make: *** [GNUmakefile:57: x64-ucrt-ruby320.rc] Error 1
make: *** Waiting for unfinished jobs....
linking miniruby.exe
x64-mingw-ucrt-fake.rb updated
```