Docs: add link to versions

CONTRIBUTING.md

@@ -146,4 +146,5 @@ When releasing a new version, these are the steps:
 - Update the dependencies with `poetry update`.
 - Run the tests.
 - Tag a release.
+- Add a new version to the `versions` variable in `docs/conf.py`.
 - Clean up the release notes on `GitHub`.

docs/_templates/versions.html

@@ -0,0 +1,12 @@
+<div role="note" aria-label="version link">
+  <h3>Versions</h3>
+    <ul class="this-page-menu">
+      <li><a href="{{ pathto('dev/' + pagename + file_suffix, true)|e }}" rel="nofollow"> {{ _('Development') }} </a></li>
+      <li><a href="{{ pathto(pagename + file_suffix, true)|e }}" rel="nofollow"> {{ _('Master') }} </a></li>
+
+      {% for version in versions %}
+      <li><a href="{{ pathto(version + '/' + pagename + file_suffix, true)|e }}" rel="nofollow"> {{ _(version) }} </a></li>
+      {% endfor %}
+
+    </ul>
+ </div>

docs/conf.py

@@ -76,6 +76,12 @@
 
 html_show_sourcelink = False
 
+html_sidebars = {
+   '**': ['localtoc.html', 'relations.html', 'sourcelink.html', 'searchbox.html', 'versions.html'],
+}
+
+html_context = {'versions': ['1.3.6']}
+
 html_theme_options = {
     "maincolor": "#228B22",
 }