Update index.md

Author: Reputeless

docs/index.md

@@ -37,4 +37,4 @@ C++17, C++20, C++23, C++26 に関��る情報を調査・提供します。
 - [sknjpn](https://twitter.com/sknjpn)
 
 #### Bronze Sponsor
-アゲハマ, Fuyutsubaki, 😊, 🐝, 野菜ジュース, jacking75, Chris Ohk, qppon, ysaito, おおやま, 🍵, lamuda, 🌻, fal_rnd, As Project, 🍑
+アゲハマ, Fuyutsubaki, 😊, 🐝, 野菜ジュース, jacking75, Chris Ohk, qppon, ysaito, おおやま, 🍵, lamuda, 🌻, fal_rnd, As Project, 🍑, IZUNA