Use new repo url

See https://grafana.com/blog/2019/01/05/moving-to-packages.grafana.com/

Author: oestrich

tasks/grafana.yml

@@ -1,12 +1,12 @@
 - name: Add apt-key
   apt_key:
-    url: https://packagecloud.io/gpg.key
+    url: https://packages.grafana.com/gpg.key
     state: present
   become: true
 
 - name: Set up apt repo for grafana
   apt_repository:
-    repo: deb https://packagecloud.io/grafana/stable/debian/ jessie main
+    repo: deb https://packages.grafana.com/oss/deb stable main
     state: present
   become: true