block merging PRs labeled as "S-waiting-on-team"

Author: japaric

.github/bors.toml

@@ -1,7 +1,7 @@
-block_labels = ["needs-decision"]
+block_labels = ["needs-decision", "S-waiting-on-team"]
 delete_merged_branches = true
 required_approvals = 1
 status = [
   "continuous-integration/travis-ci/push",
 ]
-timeout_sec = 14400
+timeout_sec = 14400