Do not ping the infrastructure team on toolstate changes

To my knowledge, there is essentially never any particular action that the
infra team needs to take on these pings, and they are currently relatively
annoying.

src/tools/publish_toolstate.py

@@ -211,14 +211,14 @@ def update_latest(
                 if new > old:
                     # things got fixed or at least the status quo improved
                     changed = True
-                    message += '🎉 {} on {}: {} → {} (cc {}, @rust-lang/infra).\n' \
+                    message += '🎉 {} on {}: {} → {} (cc {}).\n' \
                         .format(tool, os, old, new, maintainers)
                 elif new < old:
                     # tests or builds are failing and were not failing before
                     changed = True
                     title = '💔 {} on {}: {} → {}' \
                         .format(tool, os, old, new)
-                    message += '{} (cc {}, @rust-lang/infra).\n' \
+                    message += '{} (cc {}).\n' \
                         .format(title, maintainers)
                     # See if we need to create an issue.
                     if tool == 'miri':