update travis and install stretch check

.github/workflows/ansible-debian-stretch.yml

@@ -0,0 +1,16 @@
+name: Ansible check debian:stretch
+
+on: [push, pull_request]
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v2
+
+    - name: ansible check with debian:stretch
+      uses: roles-ansible/check-ansible-debian-stretch-action@master
+      with:
+        targets: "./"

.travis.yml

@@ -23,4 +23,7 @@ script:
   - echo -e "\n\n\n\n\nWe use github actions for more detailed tests.\n\nMore details about that in our github repo at:\nhttps://github.com/chaos-bodensee/role-ranger/actions\n\n\n\n\n\n"
 
 notifications:
+  email:
+    on_success: never
+    on_failure: always
   webhooks: https://galaxy.ansible.com/api/v1/notifications/