require at least one reviewer to approve PRs

Author: dhellmann

.mergify.yml

@@ -49,6 +49,7 @@ pull_request_rules:
         - "check-success=Test Ubuntu (3.11)"
         - "check-success=Test Zsh"
         - "-draft"
+        - "#approved-reviews-by>=1"
     actions:
       merge:
         method: merge