fix(provider/dcos): Fix deserialization error for DCOSAccount.Cluster…

[willgorman]

…Credential

Attempting to add a DC/OS account fails with the error

Caused by: com.fasterxml.jackson.databind.exc.InvalidDefinitionException: Cannot construct instance of `com.netflix.spinnaker.halyard.config.model.v1.providers.dcos.DCOSAccount$ClusterCredential` (no Creators, like default construct, exist): cannot deserialize from Object value (no delegate- or property-based Creator)
 at [Source: UNKNOWN; line: -1, column: -1] (through reference chain: com.netflix.spinnaker.halyard.config.model.v1.providers.dcos.DCOSAccount["clusters"]->java.util.ArrayList[0])

This appears to have been introduced with b5a09b7. I think that it may be due to changing the version of lombok and projectlombok/lombok#1563. The change in this PR is the one suggested in that issue as a way to resolve the problem and it seems to work here.

Disclaimer:

I know very little about lombok and don't know if this could break anything else. I only validated adding a DC/OS account and ran the tests for the project. I'm also not clear why this causes an issue only for DCOSAccount.ClusterCredential when it appears similar to many of the other @Data lombok classes in the project that aren't affected by this issue.

[lwander]

This change LGTM, let's see how it does in our nightly builds/deploys