[GRASS-git] [OSGeo/grass-website] dc69ea: Add DOI badge (#362)

[Veronica Andreo]

  Branch: refs/heads/master
  Home:   https://github.com/OSGeo/grass-website
  Commit: dc69ea8ebae82f3eef847c70ca9f2c391134e27a
      https://github.com/OSGeo/grass-website/commit/dc69ea8ebae82f3eef847c70ca9f2c391134e27a
  Author: Veronica Andreo <veroandreo at gmail.com>
  Date:   2023-06-04 (Sun, 04 Jun 2023)

  Changed paths:
    M content/about/license.md
    M themes/grass/layouts/index.html

  Log Message:
  -----------
  Add DOI badge (#362)

* Add DOI badge

* add doi under grass logo in the main page

* Apply suggestions from code review