Disabled semantic commit messages

ref https://docs.renovatebot.com/semantic-commits/

- we don't use semantic commits right now, so we should disable them for
  Renovate too

default.json

@@ -6,6 +6,7 @@
         ":dependencyDashboard",
         ":disableRateLimiting",
         ":maintainLockFilesWeekly",
+        ":semanticCommitsDisabled",
         "schedule:weekdays"
     ],
     "separateMultipleMajor": false,