remove old badge of nullsafty

Author: avenwu

README-zh.md

@@ -1,7 +1,6 @@
 <p align="center"><img src="https://github.com/hacktons/convex_bottom_bar/raw/master/doc/preview.png" alt="appBar preview"></p>
 <p align="center">
   <a href="https://pub.dev/packages/convex_bottom_bar"><img src="https://img.shields.io/pub/v/convex_bottom_bar.svg" alt="pub.dev"></a>
-  <a href="https://pub.dev/packages/convex_bottom_bar/versions/3.0.0-nullsafety.0"><img src="https://img.shields.io/badge/nullsafety-3.0.0-blue.svg" alt="pub.dev"></a>
   <a href="https://github.com/hacktons/convex_bottom_bar"><img src="https://img.shields.io/badge/platform-flutter-ff69b4.svg" alt="github"></a>
   <a href="https://coveralls.io/github/hacktons/convex_bottom_bar"><img src="https://coveralls.io/repos/github/hacktons/convex_bottom_bar/badge.svg" alt="coverage status"></a>
   <a href="https://pub.dev/packages/convex_bottom_bar/score"><img src="https://badges.bar/convex_bottom_bar/likes" alt="likes"></a>

README.md

@@ -1,7 +1,6 @@
 <p align="center"><img src="https://github.com/hacktons/convex_bottom_bar/raw/master/doc/preview.png" alt="appBar preview"></p>
 <p align="center">
   <a href="https://pub.dev/packages/convex_bottom_bar"><img src="https://img.shields.io/pub/v/convex_bottom_bar.svg" alt="pub.dev"></a>
-  <a href="https://pub.dev/packages/convex_bottom_bar/versions/3.0.0-nullsafety.0"><img src="https://img.shields.io/badge/nullsafety-3.0.0-blue.svg" alt="pub.dev"></a>
   <a href="https://github.com/hacktons/convex_bottom_bar"><img src="https://img.shields.io/badge/platform-flutter-ff69b4.svg" alt="github"></a>
   <a href="https://coveralls.io/github/hacktons/convex_bottom_bar"><img src="https://coveralls.io/repos/github/hacktons/convex_bottom_bar/badge.svg" alt="coverage status"></a>
   <a href="https://pub.dev/packages/convex_bottom_bar/score"><img src="https://badges.bar/convex_bottom_bar/likes" alt="likes"></a>