Fix for #1219 (sodium methods) (#1220)

* Change node-opus methods

* Try using crypto_secretbox(_open)_easy

* Wrong open method name

src/client/voice/util/Secretbox.js

@@ -1,8 +1,8 @@
 try {
   const sodium = require('sodium');
   module.exports = {
-    open: sodium.api.crypto_secretbox_open,
-    close: sodium.api.crypto_secretbox,
+    open: sodium.api.crypto_secretbox_open_easy,
+    close: sodium.api.crypto_secretbox_easy,
   };
 } catch (err) {
   const tweetnacl = require('tweetnacl');