added istambul to evm versions

src/app/tabs/compileTab/compilerContainer.js

@@ -205,6 +205,7 @@ class CompilerContainer {
       <select onchange="${this.onchangeEvmVersion.bind(this)}" class="custom-select" id="evmVersionSelector">
         <option value="default">compiler default</option>
         <option>petersburg</option>
+        <option>istanbul</option>
         <option>constantinople</option>
         <option>byzantium</option>
         <option>spuriousDragon</option>