Update mergify config

.mergify.yml

@@ -1,10 +1,28 @@
 pull_request_rules:
-  - name: Automatic merge on up to date branch with dual approval
+  - name: Automatic merge passing PR on up to date branch with approving CR
     conditions:
-      - "#approved-reviews-by>=2"
+      - "#approved-reviews-by>=1"
+      - "#review-requested=0"
+      - "#changes-requested-reviews-by=0"
+      - "#commented-reviews-by=0"
       - "status-success=continuous-integration/travis-ci/pr"
       - "label!=work-in-progress"
     actions:
       merge:
         method: merge
-        strict: true
+        strict: smart+fasttrack
+  - name: Request Brian to review changes on core api.
+    conditions:
+      - "-files~=^can/interfaces/$"
+      - "-closed"
+      - "author!=hardbyte"
+    actions:
+      request_reviews:
+        users:
+          - hardbyte
+
+  - name: delete head branch after merge
+    conditions:
+      - merged
+    actions:
+      delete_head_branch: {}

README.rst

@@ -37,6 +37,10 @@ python-can
    :target: https://codecov.io/gh/hardbyte/python-can/branch/develop
    :alt: Test coverage reports on Codecov.io
 
+.. image:: https://img.shields.io/endpoint.svg?url=https://gh.mergify.io/badges/hardbyte/python-can&style=flat
+   :target: https://mergify.io
+   :alt: Mergify Status
+
 The **C**\ ontroller **A**\ rea **N**\ etwork is a bus standard designed
 to allow microcontrollers and devices to communicate with each other. It
 has priority based bus arbitration and reliable deterministic