cli: Properly build anchor.Wallet for shell template script (#778)

cli/src/template.rs

@@ -282,8 +282,10 @@ pub fn node_shell(
 const anchor = require('@project-serum/anchor');
 const web3 = anchor.web3;
 const PublicKey = anchor.web3.PublicKey;
+const Keypair = anchor.web3.Keypair;
 
 const __wallet = new anchor.Wallet(
+  Keypair.fromSecretKey(
     Buffer.from(
       JSON.parse(
         require('fs').readFileSync(
@@ -294,6 +296,7 @@ const __wallet = new anchor.Wallet(
         ),
       ),
     ),
+  ),
 );
 const __connection = new web3.Connection("{}", "processed");
 const provider = new anchor.Provider(__connection, __wallet, {{