Update .drone.yml to v3: publish False, notify: True

Author: mohit

.drone.yml

@@ -1,14 +1,13 @@
 image: python2.7
-script:
-  - pip install -r test/requirements.txt
-  - python setup.py develop && python setup.py test
 notify:
   email:
     recipients:
-      - [email protected]
-  hipchat:
-    room: Clever-Dev-CI
-    token: {{hipchatToken}}
-    on_started: true
-    on_success: true
+    - [email protected]
+  slack:
     on_failure: true
+    on_started: false
+    on_success: false
+    webhook_url: $$slack_webhook
+script:
+- pip install -r test/requirements.txt
+- python setup.py develop && python setup.py test