To bump `setup-node@v2-beta` to `@v2`

**What happened?**
`setup-node@v2-beta` does not support `cache` option.

**What did you expect to happen?**
If the PR is opened, `setup-node@v2-beta` should be bumped to `setup-node@v2`

**What the problem might be**
Logic to bump `setup-node` version should be improved.
