Also check mima before automatic merges

Author: adamw

.mergify.yml

@@ -7,6 +7,7 @@ pull_request_rules:
     conditions:
       - author=scala-steward
       - check-success=ci
+      - check-success=mima
       - "#files=1"
       - files=build.sbt
     actions:
@@ -16,6 +17,7 @@ pull_request_rules:
     conditions:
       - author=scala-steward
       - check-success=ci
+      - check-success=mima
       - "#files=1"
       - files=project/plugins.sbt
     actions:
@@ -25,6 +27,7 @@ pull_request_rules:
     conditions:
       - author=scala-steward
       - check-success=ci
+      - check-success=mima
       - "#approved-reviews-by>=1"
     actions:
       merge:
@@ -33,6 +36,7 @@ pull_request_rules:
     conditions:
       - author=scala-steward
       - check-success=ci
+      - check-success=mima
       - "#files=1"
       - files=project/build.properties
     actions:
@@ -42,6 +46,7 @@ pull_request_rules:
     conditions:
       - author=scala-steward
       - check-success=ci
+      - check-success=mima
       - "#files=1"
       - files=.scalafmt.conf
     actions: