Add fallback_to_build_date: true

Signed-off-by: yubiuser <[email protected]>

Author: yubiuser

mkdocs.yml

@@ -235,7 +235,8 @@ extra_css:
 
 plugins:
   - search
-  - git-revision-date-localized
+  - git-revision-date-localized:
+      fallback_to_build_date: true
   - redirects:
       redirect_maps:
         'ftldns/database.md': database/index.md