use ink credentials from environment variables

config/universal.js

 const editoriaMode = require('../app/authsome_editoria')
 
+const inkUsername = process.env.INK_USERNAME
+const inkPassword = process.env.INK_PASSWORD
+
 module.exports = {
   components: [
     'pubsweet-component-ink-backend',
@@ -9,8 +12,8 @@ module.exports = {
   ],
   inkBackend: {
     inkEndpoint: 'http://ink-api.coko.foundation',
-    email: 'editoria@coko.foundation',
-    password: 'editoria'
+    email: inkUsername,
+    password: inkPassword
   },
   mode: editoriaMode,
   teams: {