Update Mergify rules (#1146)

* Update Mergify rules

This change was required due to the deprection of our current setup (https://blog.mergify.io/strict-mode-deprecation/). It was shown in the mergify results tab on our PRs and would cause the Mergify setup to fail from December on. I hope that I nowconfigured everything correctly.

* Fix mergify to use Github Actions

Author: felixdivo

.mergify.yml

@@ -1,16 +1,22 @@
+queue_rules:
+  - name: default
+    conditions:
+      - "status-success=test,format"  # "GitHub Actions works slightly differently [...], only the job name is used."
+
 pull_request_rules:
   - name: Automatic merge passing PR on up to date branch with approving CR
     conditions:
+      - "base=develop"
       - "#approved-reviews-by>=1"
       - "#review-requested=0"
       - "#changes-requested-reviews-by=0"
-      - "status-success=Travis CI - Pull Request"
+      - "status-success=test,format"
       - "label!=work-in-progress"
     actions:
-      merge:
-        method: merge
-        strict: smart+fasttrack
-  - name: Request Brian to review changes on core api.
+      queue:
+        name: default
+
+  - name: Request Brian to review changes to the core API
     conditions:
       - "-files~=^can/interfaces/$"
       - "-closed"
@@ -20,7 +26,7 @@ pull_request_rules:
         users:
           - hardbyte
 
-  - name: delete head branch after merge
+  - name: Delete head branch after merge
     conditions:
       - merged
     actions: