Add support for future post publication

build.py

@@ -122,6 +122,12 @@ class ConfigSerializer(msh.Schema):
                 f"Post slugs used multiple times: {set([item for item in slugs if slugs.count(item) > 1])}"
             )
 
+    @msh.post_load
+    def _remove_future(self, data: Dict[str, Any], *args, **kwargs) -> PostContainer:
+        posts = [item for item in data["posts"] if item.date >= datetime.date.today()]
+        data["posts"] = posts
+        return data
+
 
 def get_args() -> argparse.Namespace:
     parser = argparse.ArgumentParser()