add donate link

Author: davidism

docs/conf.py

@@ -39,6 +39,7 @@
 html_theme = 'flask'
 html_context = {
     'project_links': [
+        ProjectLink('Donate to Pallets', 'https://psfmember.org/civicrm/contribute/transact?id=20'),
         ProjectLink('Flask Website', 'https://palletsprojects.com/p/flask/'),
         ProjectLink('PyPI releases', 'https://pypi.org/project/Flask/'),
         ProjectLink('Source Code', 'https://github.com/pallets/flask/'),