Add donate sidebar to sample page

Author: dstansby

docs/conf.py

@@ -61,6 +61,12 @@
     "navbar_links": "absolute",
 }
 
+html_sidebars = {
+    "index": [
+        "donate_sidebar.html",
+    ],
+}
+
 # Add any paths that contain custom static files (such as style sheets) here,
 # relative to this directory. They are copied after the builtin static files,
 # so a file named "default.css" will overwrite the builtin "default.css".

mpl_sphinx_theme/donate_sidebar.html

@@ -1,8 +1,5 @@
-
-
-
 <div class="sidebar-donate">
-  <a href="https://numfocus.org/donate-to-matplotlib" target="_blank">
-    <span class="mpl-button" >Support Matplotlib</span>
-  </a>
-</div>
+    <a class="sd-btn sd-btn-primary sd-fs-5 sd-px-5 sd-py-2" href="https://numfocus.org/donate-to-matplotlib" target="_blank">
+      Support Matplotlib
+    </a>
+  </div>