Revert "fix: setting HMR port (close: #582) (#586)"

- Revert is because there is a better solution at #590

This reverts commit 64bb80d.

Author: ulivz

Diff for: lib/dev.js

@@ -102,7 +102,7 @@ module.exports = async function dev (sourceDir, cliOptions = {}) {
     host,
     dev: { logLevel: 'warn' },
     hot: {
-      port: parseInt(port) + 1,
+      port: port + 1,
       logLevel: 'error'
     },
     logLevel: 'error',