Fix: ts4 support

[Harris-Miller]

I can't believe I fucked this up: 8f80f42#diff-7ae45ad102eab3b6d7e7896acd08c427a9b25b346470d7bc6507b6481575d519

While testing to see if this worked

  "typesVersions": {
    "<5": {
      "index.d.ts": [
        "ts4/index.d.ts"
      ],
      "*": [
        "ts4/*"
      ]
    }
  },

I was adding/removing it locally while testing it against a local repo with typescript@4. It worked as expected, and then, with it still removed, committed it 🤦

This will re-fix ts4 support

How I tested this

• Pull this repo: https://github.com/Harris-Miller/ramda-ts4-test and npm ci
• It's a simple project that uses the 2 ts@5 only functions pick and omit
• The project has ts@4 installed, so npm run build will have typescript errors
• Pull down this branch, npm run build
• Using yalc, do yalc publish
• back over in ramda-ts4-test do yalc link types-ramda
• do npm run build again see the type errors are gone