0.2.5

• Fixed revealjs html export style bug.

• Supported configuring attributes for diagram containers.
  For example:

    ```puml {.center}
    // your code here
    ```
  

  will add class="center" to the container.

• By default, all exported files will use github-light.css style. You can use your preview theme for export by setting printBackground to true from the extension settings, or add print_background:true to front-matter.