title: @ConfigurationProperties does not use PropertySourcesPlaceholderConfigurer
body: <p><code>PropertySourcesPlaceholderConfigurer</code> works for my <code>@Value</code>s but not used for the following advertised datasource configuration    </p>
  
  <pre><code>@Bean
  @ConfigurationProperties(prefix = "datasource")
  public DataSource dataSource() {
      return DataSourceBuilder.create().build();
  }
  </code></pre>
  
  <p>I customized <code>PropertySourcesPlaceholderConfigurer</code> to decode passwords in configuration file but decoding functionality is not triggered for this exact place, while it works in other places. Could you please advise?</p>