Fix untrusted build cache (#2033)

diff --git a/buildkite/bazelci.py b/buildkite/bazelci.py
index c37c62f..90a2572 100755
--- a/buildkite/bazelci.py
+++ b/buildkite/bazelci.py
@@ -1903,8 +1903,7 @@
         # Use RBE for caching builds running on GCE.
         remote_cache_flags = []
         if is_mac():
-            # unStrusted -> Yes, the untrusted bucket name contains a typo :(
-            bucket_id = "trusted" if THIS_IS_TRUSTED else "unstrusted"
+            bucket_id = "trusted" if THIS_IS_TRUSTED else "untrusted"
             remote_cache_flags = [
                 f"--remote_cache=https://storage.googleapis.com/bazel-{bucket_id}-build-cache"
             ]