chore(ci): Remove Gitter.im webhooks from CI services

This removes notification webhook configurations from
our CI services, in anticipation of shutdown of the Gitter channel.

Change-Type: patch

.travis.yml

@@ -67,9 +67,3 @@ deploy:
 
 notifications:
   email: false
-  webhooks:
-    urls:
-      - https://webhooks.gitter.im/e/0a019c8b9828eb9f6a72
-    on_success: change
-    on_failure: always
-    on_start: never

appveyor.yml

@@ -48,11 +48,3 @@ test_script:
 
 deploy_script:
   - if %APPVEYOR_REPO_BRANCH%==master (bash .\scripts\ci\deploy.sh -o win32 -r %Platform%)
-
-notifications:
-
-  - provider: Webhook
-    url: https://webhooks.gitter.im/e/0becb34b32e20d389bb8
-    on_build_success: false
-    on_build_failure: true
-    on_build_status_changed: true