Commented out Slack config as it stopped service from running

Signed-off-by: Brian Christner <brian.christner@gmail.com>

alertmanager/config.yml

@@ -1,10 +1,10 @@
-route:
-    receiver: 'slack'
+ route:
+     receiver: 'slack'
 
-receivers:
-    - name: 'slack'
-      slack_configs:
-          - send_resolved: true
-            username: '<username>'
-            channel: '#<channel-name>'
-            api_url: '<incomming-webhook-url>'
+ receivers:
+     - name: 'slack'
+#       slack_configs:
+#           - send_resolved: true
+#             username: '<username>'
+#             channel: '#<channel-name>'
+#             api_url: '<incomming-webhook-url>'