ListTasks: proposed filters

[adamstruck]

Filter on tags and/or state.

Funnel has been using these filters since February and it seems to be sufficient for our use cases.

[delagoya]

@adamstruck Is this still a request for schema enhancement? Given the move to OAS, would you like to propose this as a new PR on the swagger schema?

[adamstruck]

Once #111 and #113 are in I will update this PR to be against the swagger definitions.

[susheel]

@adamstruck Could you update this PR to the new YAML spec in develop

[adamstruck]

I updated the PR.

Unfortunately, the proposed tags filter can't be expressed as a query parameter in openAPI 2.0.

[kellrott]

So theoretically we could get the tags field as a json map in openAPI 3.0? But we're not sure if the rest of the GA4GH group wants to move there yet?

[vsmalladi]

@kellrott has this been addressed by #170 and can we close this?