Update appveyor.yml

Author: ejsmith

appveyor.yml

@@ -31,7 +31,7 @@ notifications:
   - provider: Slack
     auth_token:
       secure: PigIGGo7UUDwdb0KGM/s7OfpAng/OMJx7q33jKfzudFBiXi1EBEd0DRmkbCc7CiX
-    channel: notifications
+    channel: '#notifications'
 
 artifacts:
   - path: Build\Deploy\packages\*.nupkg
@@ -40,4 +40,4 @@ deploy:
   - provider: Environment
     name: MyGet
     on:
-      branch: master
+      branch: master