🎨 Trying to make Mergify use the merge queue (ITISFoundation#7116)

Co-authored-by: Andrei Neagu <[email protected]>

.github/mergify.yml

@@ -1,46 +1,46 @@
-pull_request_rules:
-    - name: Automatic merge
-      description: Conditions required for automatic merging of a PR
-      conditions:
-        # let Mergify know that the PR can be merged (added manually)
-        - label = 🤖-automerge
-        # block Mergify from merging the PR (added manually)
-        - label != 🤖-do-not-merge
-
-        # list of CI checks that need to pass in order for the PR to be merged
-        - check-success=unit-tests
-        - check-success=integration-tests
-        - check-success=system-tests
+queue_rules:
+  - name: default
+    queue_conditions:
+      # general prerequisits fo accept the PR in the queue
+      - label=🤖-automerge # let Mergify know that the PR can be merged (added manually)
+      - label!=🤖-do-not-merge # block Mergify from merging the PR (added manually)
+      - base=master
+      - -draft # PR is not in draft state
+      - -conflict # No merge conflicts
 
-        # Check for required reviews
-        - "#approved-reviews-by>=2"  # Requires 2 approving reviews
-        - "#changes-requested-reviews-by=0"  # No changes requested
-        - "#review-threads-unresolved=0"  # All review threads resolved
+      # Check for required reviews
+      - "#approved-reviews-by>=2" # Requires 2 approving reviews
+      - "#changes-requested-reviews-by=0" # No changes requested
+      - "#review-threads-unresolved=0" # All review threads resolved
 
-        # Optional but recommended checks
-        - base=master
-        - -draft  # PR is not in draft state
-        - -conflict  # No merge conflicts
-      actions:
-        merge:
+    merge_conditions:
+      # list of CI checks that need to pass
+      - check-success=unit-tests
+      - check-success=integration-tests
+      - check-success=system-tests
 
-    - name: automatic update for PR ready to be merged
-      conditions:
-        - -draft
-        - label=🤖-automerge
-      actions:
-        update:
+pull_request_rules:
+  - name: update branch if behind master
+    conditions:
+      - queue-name=default # only run if already queued
+      - label=🤖-automerge
+      - label!=🤖-do-not-merge
+      - base=master
+    actions:
+      update:
 
-    - name: retry CI on failure
-      conditions:
-        - base=master
-        - or:
+  - name: retry CI on fails (used for flaky tests)
+    conditions:
+      - queue-name=default # only run if already queued
+      - label=🤖-automerge
+      - label!=🤖-do-not-merge
+      - base=master
+      - or:
           - check-failure=unit-tests
           - check-failure=integration-tests
           - check-failure=system-tests
-      actions:
-        github_actions:
-          workflow:
-            dispatch:
+    actions:
+      github_actions:
+        workflow:
+          dispatch:
             - workflow: .github/workflows/ci-testing-deploy.yml
-