Remove only-allow pre-install due to issue installing with npm

Fixes #152. This seems
to be due to a bug in only-allow that specifically affects `npm`, where
the `only-allow` goes into effect even when installing the package as a
dependency: pnpm/only-allow#13

package.json

@@ -66,7 +66,6 @@
  "lint": "eslint --ext .js,.jsx,.ts,.tsx src --fix",
  "lint:check": "eslint --ext .js,.jsx,.ts,.tsx src",
  "md-link:check": "markdown-link-check -v -p *.md -c .markdown-link-check-config.json",
- "preinstall": "npx only-allow pnpm",
  "test": "vitest run",
  "test:watch": "vitest watch",
  "test:coverage": "vitest run --coverage",