Fix broken windows CI
Fix broken windows CI

It turns out our cache was always missing because of backslashes in the cache keys.
The problem was exposed when I tightened up the non-hermetic action reads in https://github.com/bazelbuild/rules_typescript/commit/d1c107e4c62ced467fa17db0e56de3dc20001b72

PiperOrigin-RevId: 194609051

bazelbuild/rules_typescript,bazelbuild/rules_typescript,bazelbuild/rules_typescript