docs: add sponsorship banner (#2611)

Author: Kludex

docs/overrides/main.html

@@ -0,0 +1,14 @@
+{% extends "base.html" %}
+
+{% block announce %}
+<style>
+    div[data-md-component="announce"] {
+        background-color: #f0f8ff;  /* Light blue */
+        color: #333;
+    }
+    div[data-md-component="announce"] a {
+        color: #0366d6;
+    }
+</style>
+     If you're using uvicorn in production, please consider <a href="/sponsorship">sponsoring the project</a> to help with maintenance and development. ✨
+{% endblock %}

mkdocs.yml

@@ -33,6 +33,7 @@ theme:
     - navigation.tracking
     - navigation.footer # https://squidfunk.github.io/mkdocs-material/upgrade/?h=content+copy#navigationfooter
     - toc.follow # https://squidfunk.github.io/mkdocs-material/setup/setting-up-navigation/#anchor-following
+    - announce.dismiss # https://squidfunk.github.io/mkdocs-material/setup/setting-up-the-header/#mark-as-read
 
 repo_name: encode/uvicorn
 repo_url: https://github.com/encode/uvicorn