title: How to I use a yaml selector?
body: <p>I am experimenting with yaml selectors, so far without success.  My selectors.yml:</p>
  <pre class="lang-yaml prettyprint-override"><code>selectors:
    - name: daily
      description: selects models for daily run
      definition:
        exclude:
          - union:
              - &quot;tag:pp_backfill&quot;
              - &quot;tag:inc_transactions_raw_data&quot;
              - &quot;tag:hourly&quot;
  </code></pre>
  <p>And when I try to use it I get an error:</p>
  <pre><code>$ dbt ls --selector daily
  * Deprecation Warning: dbt v0.17.0 introduces a new config format for the
  dbt_project.yml file. Support for the existing version 1 format will be removed
  in a future release of dbt. The following packages are currently configured with
  config version 1:
   - honey_dbt
   - dbt_utils
   - audit_helper
   - codegen
  
  For upgrading instructions, consult the documentation:
    https://docs.getdbt.com/docs/guides/migration-guide/upgrading-to-0-17-0
  
  * Deprecation Warning: The &quot;adapter_macro&quot; macro has been deprecated. Instead,
  use the `adapter.dispatch` method to find a macro and call the result.
  adapter_macro was called for: dbt_utils.intersect
  Encountered an error:
  Runtime Error
    Could not find selector named daily, expected one of []
  </code></pre>
  <p>I tried this in both 0.18.1 and 0.19.0, with and without <code>config-version: 2</code>.  Any thoughts?</p>