fix user's name can be None

Author: RuslanUC

pyproject.toml

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "t-export"
-version = "0.1.3b2"
+version = "0.1.3b3"
 description = "Telegram chats export tool."
 authors = ["RuslanUC <dev_ruslan_uc@protonmail.com>"]
 readme = "README.md"

texport/html/avatar.py

@@ -16,7 +16,7 @@ def to_html(self) -> str:
         return f"""
         <div class="pull_left userpic_wrap{forward}">
             <div class="userpic userpic8" style="width: 42px; height: 42px">
-                <div class="initials" style="line-height: 42px">{name[0]}</div>
+                <div class="initials" style="line-height: 42px">{name[0] if name is not None else "N"}</div>
             </div>
         </div>
         """