Update release_template.txt to be markdown

Author: jasongrout

scripts/release_template.txt

@@ -1,18 +1,14 @@
-`v{{ version }} <https://github.com/jupyter-widgets/ipywidgets/releases/tag/v{{ version }}>`__
----------------------------------------------------------------------------
+### [v{{ version }}](https://github.com/jupyter-widgets/ipywidgets/releases/tag/v{{ version }}) ({{ close_date }})
 
-{{ close_date }}
-^^^^^^^^^^^^^^^
-
-See the `ipywidgets
-{{ version }} <https://github.com/jupyter-widgets/ipywidgets/milestone/XXXX?closed=1>`__
+See the [ipywidgets
+{{ version }}](https://github.com/jupyter-widgets/ipywidgets/milestone/XXXX?closed=1)
 milestone on GitHub for the full list of pull requests and issues closed.
 
 {%   for pr in pull_requests -%}
-* {{ pr['title'] | capitalize }} (`#{{ pr['number'] }} <{{pr['html_url']}}>`__
+* {{ pr['title'] | capitalize }} ([#{{ pr['number'] }}]({{pr['html_url']}})
 {%-      if pr['loghub_related_issues']|length %}
 {%-          for pri in pr['loghub_related_issues'] -%}
-                 , `#{{ pri['text'] }} <{{ pri['url'] }}>`__
+                 , [#{{ pri['text'] }}]({{ pri['url'] }})
 {%-          endfor -%}
 {%- endif %})
 {%   endfor %}