Don't run coverage for now

We need greenmail-mail-test/greenmail#284 to
be resolved first, because native-tls uses an up-to-date openssl
version, which rejects Greenmail's cert

azure-pipelines.yml

@@ -70,6 +70,7 @@ stages:
    jobs:
      - template: azure/style.yml@templates
  - stage: coverage
+   condition: never() # https://github.com/greenmail-mail-test/greenmail/issues/284
    displayName: Code coverage
    dependsOn: test
    jobs:
@@ -89,7 +90,7 @@ resources:
       endpoint: jonhoo
   containers:
    - container: greenmail
-     image: greenmail/standalone:1.5.9
+     image: greenmail/standalone:1.5.10
      ports:
        - 3025:3025
        - 3110:3110