latest municipality key added to pkgdown

Author: Markus Kainu

_pkgdown.yml

@@ -34,6 +34,7 @@ reference:
     geofi comes with a timeseries of built-in municipality keys that can be used to aggregate municipality level data (`municipality_key_*`) and `municipality_central_localities` data containing point locations for cental locality of each municipality
   contents:
   - municipality_key
+  - municipality_key_2026
   - municipality_key_2025
   - municipality_key_2024
   - municipality_key_2023