Update README.md

Author: huextrat

README.md

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+<h1 align="center" >The code is no longer maintained</h1>
+
 <h1 align="center">CryptoShadow <img src="https://hugoextrat.com/images/ic_launcher.png" alt="Flutter" width="50" height="50" /></h1>
 
 <div align="center">
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   </h3>
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-<div align="center">
-  <a href='https://play.google.com/store/apps/details?id=com.huextrat.cryptoshadow'><img width="320" height="130" alt='Get in on Google Play' src='https://play.google.com/intl/en_us/badges/images/generic/en_badge_web_generic.png'/></a>
-</div>
 <div align="center">
   <strong>CryptoCurrency Tracker for Android & iOS</strong>
 </div>