Add const to requireRegex

[pete-murphy]

Description of the change

Importing from React.Basic.Hooks is broken (see #236).
This seems to be because the requireRegex used by parseDeps only parses required modules using the var keyword, while recent updates to React.Basic modules switched from var to const.

This PR updates the requireRegex to match on

const React = require("react")

in addition to the existing supported format

var React = require("react")

Before

Note that the React "shim" (from `https://unpkg.com/[email protected]/umd/react.development.js`) is not included in *Sources*

After

---

Checklist:

• Added the change to the changelog's "Unreleased" section with a reference to this PR (e.g. "- Made a change (#0 by @)")
• Linked any existing issues or proposals that this pull request should close
• Updated or added relevant documentation
• Added a test for the contribution (if applicable)

[thomashoneyman]

Thank you!

[thomashoneyman]

Deployed in:
https://github.com/purescript/trypurescript/releases/tag/v2021-07-04.1