fix cannot update verbio engine_version (#327)

lib/routes/api/speech-credentials.js

@@ -458,6 +458,7 @@ router.put('/:sid', async(req, res) => {
           options,
           deepgram_stt_uri,
           deepgram_stt_use_tls,
+          engine_version
         } = req.body;
 
         const newCred = {
@@ -484,6 +485,7 @@ router.put('/:sid', async(req, res) => {
           options,
           deepgram_stt_uri,
           deepgram_stt_use_tls,
+          engine_version
         };
         logger.info({o, newCred}, 'updating speech credential with this new credential');
         obj.credential = encryptCredential(newCred);