DOC: add dropdown

Author: jklymak

doc/_static/switcher.json

@@ -0,0 +1,33 @@
+[
+    {
+        "name": "stable",
+        "version": "stable"
+    },
+    {
+        "name": "devel",
+        "version": "devel"
+    },
+    {
+        "version": "3.5.0"
+    },
+    {
+        "name": "3.4",
+        "version": "3.4.3"
+    },
+    {
+        "name": "3.3",
+        "version": "3.3.4"
+    },
+    {
+        "name": "3.2",
+        "version": "3.2.2"
+    },
+    {
+        "name": "3.1",
+        "version": "3.1.3"
+    },
+    {
+        "name": "3.0",
+        "version": "3.0.3"
+    },
+]

doc/conf.py

@@ -323,6 +323,10 @@ def matplotlib_reduced_latex_scraper(block, block_vars, gallery_conf,
     # and CI builds https://github.com/pydata/pydata-sphinx-theme/pull/386
     "collapse_navigation": not is_release_build,
     "show_prev_next": False,
+    "switcher": {
+        "json_url": "https://matplotlib.org/en/latest/_static/switcher.json",
+        "url_template": "https://matplotlib.org/{version}/"
+    }
 }
 include_analytics = is_release_build
 if include_analytics: