WEB: update web/pandas/versions.json for docs dropdown menu (pandas-dev#45555)

Author: simonjayhawkins

web/pandas/versions.json

@@ -4,13 +4,9 @@
         "version": "docs/dev"
     },
     {
-        "name": "1.4 (rc)",
+        "name": "1.4 (stable)",
         "version": "pandas-docs/version/1.4"
     },
-    {
-        "name": "1.3 (stable)",
-        "version": "docs"
-    },
     {
         "name": "1.3",
         "version": "pandas-docs/version/1.3"