onChange handler doesn't work with withFormik

## 🐛 Bug report

### Current Behavior

When using withFormik, the handleChange function is not called when passed in via props. However, the input onChange event will call a local change handler function.

### Expected behavior

handleChange function from props should be called

### Reproducible example

https://codesandbox.io/embed/withformik-codesandbox-template-xolcc

### Your environment

| Software | Version(s) |
| ---------------- | ---------- |
| Formik | 1.5.8
| React | 16.8.6
| TypeScript |
| Browser |
| npm/Yarn |
| Operating System | macOS

Start with the linked CodeSandbox reproduction and trace the withFormik entry point, comparing the prop-supplied handleChange path with the local input onChange handler. Done means the handleChange function passed through props is called when the input changes, while the reproduction continues to behave as expected.

Written by the indexing model from the issue text.