Mergify it! (#269)

* Mergify it!

* auto-merge for scala-steward

* revert scala-steward auto-merge

Author: octonato

.mergify.yml

@@ -0,0 +1,28 @@
+
+pull_request_rules:
+  - name: Merge PRs that are ready
+    conditions:
+      - status-success=Travis CI - Pull Request
+      - status-success=typesafe-cla-validator
+      - "#approved-reviews-by>=1"
+      - "#review-requested=0"
+      - "#changes-requested-reviews-by=0"
+      - label!=status:block-merge
+    actions:
+      merge:
+        method: squash
+        strict: smart
+        
+  - name: Delete the PR branch after merge
+    conditions:
+      - merged
+    actions:
+      delete_head_branch: {}
+
+  - name: auto add wip
+    conditions:
+      # match a few flavours of wip
+      - title~=^(\[wip\]( |:) |\[WIP\]( |:) |wip( |:) |WIP( |:)).*
+    actions:
+      label:
+        add: ["status:block-merge"]